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Strona główna » Instytut » Pracownicy » Wiesław Ignacy Gruszecki

prof. dr hab. Wiesław Ignacy Gruszecki

Zakład

Zakład Biofizyki

Stanowisko:

profesor zwyczajny

Kontakt:

pokój: 201
telefon: (081) 537-62-52
e-mail: wieslaw.gruszecki@umcs.pl

W IF UMCS od roku:

1983

Specjalność naukowa:

biofizyka

Funkcje pełnione w IF UMCS:

Kierownik Zakładu Biofizyki

2006 - 2008 Dyrektor Instytutu Fizyki

Zainteresowania naukowe:

badanie transportu energii wzbudzenia elektronowego w fotosyntezie

badanie własności strukturalnych i dynamicznych błon lipidowych (wpływ karotenoidów i antybiotyków polienowych)

Kariera zawodowa naukowo - dydaktyczna:

1984 - magisterium, UMCS Lublin
1986 - doktorat, UMCS Lublin
1993 - habilitacja, UJ Kraków
1999 - tytuł profesora

Kariera zawodowa - praktyka:

1983 - 1984 asystent techniczny (podczas V roku studiów)
1984 - 1987 asystent
1987 - 1996 adiunkt
1996 - 2003 profesor nadzwyczajny
2003 - profesor zwyczajny 




Kariera zawodowa - inne formy działalności:

Staże naukowe 

Kanada - Universite du Quebeck a Trois-Rivieres - staż postdoktorski 1989 - 1990

Francja  - Dep. Physiol. Veget. et Ecosystemes, Centre Cadarache, 1991, 6 tygodni

Szwajcaria  - Laboratorie de Bioenergetique Universite de Geneve, stypendium Rządu Szwajcarskiego 1991/93, 4 miesiące

Niemcy  - Universitaet Bielefeld Universitaet Muenchen stypendium Deutsche Forschungsgemeinschaft 1993-98, łącznie 5 miesięcy

USA  - University of California Los Angeles „visiting scholar” 1998, 3 miesiące , 1999, 3 miesiące 2001, 3 miesiące

Niemcy  - Max-Born-Institut, Berlin Projekt badawczy DFG 2004, 2 miesiące

Niemcy  - Universitaet Potsdam „visiting scholar” 2006, 2 miesiące




Członkostwo w towarzystwach i organizacjach:

Komitet Biochemii i Biofizyki PAN

Polskie Towarzystwo Biofizyczne

Polskie Towarzystwo Fizyczne

International Carotenoid Society

Zainteresowania i pasje:

Muzyka symfoniczna, skrzypcowa, organowa i oratoryjna

Jazz

Folk słowiański i Romanse rosyjskie

Teatr i Malarstwo Europejskie XIX i XX w.

Gotowanie

Inne:

żona Ewa,

troje dzieci: Natalia, Ignacy, Maria

Publikacje: Ukryj abstrakty

  1. W. I. Gruszecki, Light-driven regulatory mechanisms in the photosynthetic antenna complex LHCII, Biochemical Society Transactions, 38(), 2010, 702-704

  2. W. I. Gruszecki,M. Zubik,R. Luchowski,E. Janik,W. Grudziński,M. Gospodarek,J. Goc,L. Fiedor,Z. Gryczynski,I. Gryczynski, Photoprotective role of the xanthophyll cycle studied by means of modeling of xanthophyll-LHCII interactions, Chemical Physics, 373(), 2010, 122-128

  3. W. I. Gruszecki,R. Luchowski,M. Zubik,W. Grudziński,E. Janik,M. Gospodarek,J. Goc,Z. Gryczynski,I. Gryczynski, Blue-light-controlled photoprotection in plants at the level of the photosynthetic antenna complex LHCII, Journal of Plant Physiology, 167(), 2010, 69-73

  4. E. Janik,W. Maksymiec,W. I. Gruszecki, The photoprotective mechanisms in Secale cereale leaves under Cu and high light stress condition, Journal of Photochemistry and Photobiology B, 101(), 2010, 47-52

  5. I. Rumak,K. Gieczewska,B. Kierdaszuk,W. I. Gruszecki,A. Mostowska,R. Mazur,M. Garstka, 3-D modelling of chloroplast structure under (Mg2+) magnesium ion treatment. Relationship between thylakoid membrane arrangement and stacking, Biochimica et Biophysica Acta -Bioenergetics, 1797(), 2010, 1736-1748

  6. M. Kulma,M. Hereć,W. Grudziński,G. Anderluh,W. I. Gruszecki,K. Kwiatkowska,A. Sobota, Sphingomyelin-rich domains are sites of lysenin oligomerization: Implications for raft studies, Biochimica et Biophysica Acta -Biomembranes, 1798(), 2010, 471-481

  7. E. Janik,W. Maksymiec,R. Mazur,M. Garstka,W. I. Gruszecki, Structural and Functional Modifications of the Major Light-Harvesting Complex II in Cadmium- or Copper-Treated Secale cereale, Plant and Cell Physiology, 51(), 2010, 1330-1340

  8. W. I. Gruszecki, R. Luchowski, M. Gagos, M. Arczewska, P. Sarkar, M. Herec, B. Mysliwa-Kurdziel, K. Strzalka, I. Gryczynski, Z. Gryczynski, Molecular organization of antifungal antibiotic amphotericin B in lipid monolayers studied by means of Fluorescence Lifetime Imaging Microscopy, Biophysical Chemistry, 143(), 2009, 95-101

  9. W. I. Gruszecki, M. Gospodarek, W. Grudziński, R. Mazur, K. Gieczewska, M. Garstka, Light-induced Change of Configuration of the LHCII-Bound Xanthophyll (Tentatively Assigned to Violaxanthin): A Resonance Raman Study, Jorunal Physics Chemistry B, 113(), 2009, 2506-2512

  10. W. I. Gruszecki, E. Janik, R. Luchowski, P. Kernen, W. Grudziński, I. Gryczynski, Z. Gryczynski, Supramolecular Organization of the Main Photosynthetic Antenna Complex LHCII: A Monomolecular Layer Study, Langmuir, 25(), 2009, 9384–9391

  11. J. Widomska, A. Kostecka-Gugala, D. Latowski, W. I. Gruszecki, K. Strzalka, Calorimetric studies of the effect of cis-carotenoids on the thermotropic phase behavior of phosphatidylcholine bilayers, Biophysical Chemistry, 140(), 2009, 108-114

  12. K. Olejnik, D. Plochocka, M. Grynberg, G. Goch, W. I. Gruszecki, T. Basinska, E. Kraszewska, Mutational analysis of the AtNUDT7 Nudix hydrolase from Arabidopsis thaliana reveals residues required for protein quaternary structure formation and activity, Acta Biochimica Polonica, 56(), 2009, 291-300

  13. Marczak, M. Mazur, A. Gruszecki, W. Skorupska, A., PssO a unique extracellular protein important for exopolysaccharide synthesis in Rhizobium leguminosarum bv. trifolii, Biochimie, 90(), 2008, 1781-1790

  14. Grzyb, J. Gagoś, M. Gruszecki, W. Bojko, M. Strzałka , K., Interaction of ferredoxin:NADP+ oxidoreductase with model membranes, Biochimica et Biophysica Acta- Biomembranes, 1778(), 2008, 133-142

  15. Hereć, M. Gagoś, M. Kulma, M. Kwiatkowska, K. Sobota, A. Gruszecki, W., Secondary structure and orientation of the pore-forming toxin lysenin in a sphingomyelin-containing membrane, Biochimica et Biophysica Acta- Biomembranes, 1778(), 2008, 872-879

  16. Kupisz, K. Sujak, A. Patyra, M. Trębacz, K. Gruszecki, W., Can membrane-bound carotenoid pigment zeaxanthin carry out a transmembrane proton transfer?, Biochimica et Biophysica Acta- Biomembranes, 1778(), 2008, 2334-2340

  17. Okulski, W. Sujak, A. Gruszecki, W., Dipalmitoylphosphatidylcholine membranes modified with carotenoid pigment lutein: Experiment versus Monte Carlo simulation study of the membrane organization, Biochimica et Biophysica Acta- Biomembranes, 1778(), 2008, 2105-2118

  18. Gagoś, M. Gruszecki, W., Organization of polyene antibiotic amphotericin B at the argon-water interface, Biophysical Chemistry, 137(), 2008, 110-115

  19. Gagoś, M. Hereć, M. Arczewska, M. Czernel, G. Dalla Serra, M. Gruszecki, W., Anomalously high aggregation level of the polyene antibiotic amphotericin B in acidic medium: implications for the biological action, Biophysical Chemistry, 136(), 2008, 44-49

  20. Gruszecki, W. Janik, E. Grudzinski, W. Kernen, P. Gospodarek, M. Maksymiec, W. Krupa, Z., Specific molecular aggregation of photosynthetic pigment-protein complex LHCII, Single Molecule Spectroscopy and Imaging - Proceedings of SPI, (), 2008, 6862, 68620W-1-8

  21. Janik, E. Grudziński, W. Gruszecki, W. Krupa, Z., The xanthophyll cycle pigments in Secale cereale leaves under combined Cd and high light stress conditions, Journal of Photochemistry and Photobiology B: Biology, 90(), 2008, 47-52

  22. Sujak, A. Gagos, M. Serra, M.D. Gruszecki, W.I., Organization of two-component monomolecular layers formed with dipalmitoylphosphatidylcholine and the carotenoid pigment, canthaxanthin, Molecular Membrane Biology, 24(5-6), 2007, 431-441

    Abstract:
    Canthaxanthin is a carotenoid pigment of physiological importance owing to potential modulation of the dynamic and structural properties of biomembranes. The effect of canthaxanthin on the organization of lipid membranes formed with dipalmitoylphosphatidylcholine ( DPPC) was studied with application of monomolecular layer technique, FTIR spectroscopy and linear dichroism- FTIR. The specific molecular areas of the two- component monomolecular layers of canthaxanthin- DPPC show pronounced underadditivity in the concentration range below 2 mol% carotenoid with respect to the lipid, corresponding to the monomeric organization of the pigment. Additionally, the analysis of the FTIR spectra of the two- component monolayers deposited to the solid support shows that organization of the carotenoid in the lipid monolayer is governed primarily by van der Waals interactions between the pigment chromophore and lipid alkyl chains. This interaction is responsible for an ordering effect of canthaxanthin with respect to lipids. Analysis of FTIR spectra of two- component monolayers suggests the possibility of hydrogen bonding between the lipid polar headgroups and the keto groups of canthaxanthin via water bridges.

  23. Herec, M. Islamov, A. Kuklin, A. Gagos, M. Gruszecki, W.I., Effect of antibiotic amphotericin B on structural and dynamic properties of lipid membranes formed with egg yolk phosphatidylcholine, Chemistry And Physics Of Lipids, 147(2), 2007, 78-86

    Abstract:
    Amphotericin B (AmB) is a popular antibiotic applied in treatment of deep-seated mycotic infections. The mode of action of AmB is based upon interactions with biomembranes but exact binding properties of the antibiotic to the lipid membranes still remain obscure. Effect of incorporation of AmB into egg yolk phosphatidylcholine membranes in the concentration range from 0.01 to 5 mol% on structural and dynamic properties of lipid bilayers was studied with application of small-angle neutron scattering, X-ray diffractometry and Fourier-transform infrared spectroscopy (FTIR). The results of the experiments show that AmB is located predominantly in the headgroup region of the membranes at concentrations below I mol%. The process of AmB aggregation, at concentrations above 1 mol%, is associated with ordering effect within the acyl chain region and therefore indicates incorporation of AmB into the hydrophobic membrane core. (c) 2007 Elsevier Ireland Ltd. All rights reserved.

  24. Pawllikowska-Pawlega, B. Gruszecki, W.I. Misiak, L. Paduch, R. Piersiak, T. Zarzyka, B. Pawelec, J. Gawron, A., Modification of membranes by quercetin, a naturally occurring flavonoid, via its incorporation in the polar head group, Biochimica et Biophysica Acta – Biomembranes , 1768(), 2007, 2195-2204

    Abstract:
    Quercetin is a naturally occurring flavonoid that has a lot of beneficial properties to human health. In this report, using the spin label technique, the influence of quercetin on the fluidity of multilamellar DPPC liposomes was studied. The polarity of the environment preferred by quercetin was also examined by determining the dependence of the position of electronic absorption maxima on dielectric properties of different environments. Autofluorescence of quercetin was also used to examine its distribution in cells. An additional aim of the study was to find how quercetin presence affects human skin fibroblasts. The results showed that incorporation of quercetin at physiological pH into DPPC liposomes caused changes in the partition coefficient of the Tempo spin label between water and polar head group phases. By determining the electronic absorption maxima, we observed that the chromophore of quercetin is localized in the polar head region. Fluorescence microscopy of HSF cells showed quercetin presence in the membrane, cytoplasm and inside the nucleus. Ultrastructural observation revealed some changes, especially in membranous structures, after flavonol treatment. From the results we have concluded that quercetin present in the membrane and other structures can cause changes within cells crucial for its pharmacological activity. © 2007 Elsevier B.V. All rights reserved.

  25. Sujak, A. Strzałka, K. Gruszecki, W.I., Thermotropic phase behaviour of lipid bilayers containing carotenoid pigment cathaxanthin: a differential scanning calorimetry study, Chemistry and Physics of Lipids, 145(), 2007, 1-12

  26. Legall, H. Stiel, H. Beck, M. Leupold, D. Gruszecki, W.I. Lokstein, H. , Near edge X-ray absorption fine structure spectroscopy (NEXAFS) of pigment-protein complexes: Peridinin-chlorophyll a protein (PCP) of Amphidinium carterae, Journal of Biochemical and Biophysical Methods, 70(), 2007, 369-376

  27. Gruszecki, W. I. Grudzinski, W. Gospodarek, M. Patyra, M. Maksymiec, W., Xanthophyll-induced aggregation of LHCII as a switch between light-harvesting and energy dissipation systems, Biochimica Et Biophysica Acta-Bioenergetics, 1757(11), 2006, 1504-1511

    Abstract:
    The xanthophyll cycle pigments, violaxanthin and zeaxanthin, present outside the light-harvesting pigment-protein complexes of Photosystem II (LHCII) considerably enhance specific aggregation of proteins as revealed by analysis of the 77 K chlorophyll a fluorescence emission spectra. Analysis of the infrared absorption spectra in the Amide I region shows that the aggregation is associated with formation of intermolecular hydrogen bonding between the a helices of neighboring complexes. The aggregation gives rise to new electronic energy levels, in the Soret region (530 nm) and corresponding to the Q spectral region (691 nm), as revealed by analysis of the resonance light scattering spectra. New electronic energy levels are interpreted in terms of exciton coupling of protein- bound photosynthetic pigments. The energy of the Q excitonic level of chlorophyll is not high enough to drive the light reactions of Photosystem II but better suited to transfer excitation energy to Photosystem I, which creates favourable energetic conditions for the state I-state II transition. The lack of fluorescence emission from this energy level, at physiological temperatures, is indicative of either very high thermal energy conversion rate or efficient excitation quenching by carotenoids. Chlorophyll a fluorescence was quenched up to 61% and 34% in the zeaxanthin- and violaxanthin- containing samples, respectively, as compared to pure LHCII. Enhanced aggregation of LHCII, observed in the presence of the xanthophyll cycle pigments, is discussed in terms of the switch between light-harvesting and energy dissipation systems. (c) 2006 Elsevier B.V. All rights reserved.

  28. Marczak, M. Mazur, A. Krol, J. E. Gruszecki, W. I. Skorupska, A., Lipoprotein PssN of Rhizobium leguminosarum bv. trifolii: Subcellular localization and possible involvement in exopolysaccharide export, Journal of Bacteriology, 188(19), 2006, 6943-6952

    Abstract:
    Surface expression of exopolysaccharides (EPS) in gram-negative bacteria depends on the activity of proteins found in the cytoplasmic membrane, the periplasmic space, and the outer membrane. pssTNOP genes identified in Rhizobium leguminosarum bv. trifolii strain TA1 encode proteins that might be components of the EPS polymerization and secretion system. In this study, we have characterized PssN protein. Employing pssN- phoA and pssN-lacZ gene fusions and in vivo acylation with [H- 3] palmitate, we demonstrated that PssN is a 43-kDa lipoprotein directed to the periplasm by an N-terminal signal sequence. Membrane detergent fractionation followed by sucrose gradient centrifugation showed that P`ssN is an outer membrane- associated protein. Indirect immunofluorescence with anti-PssN and fluorescein isothiocyanate-conjugated antibodies and protease digestion of spheroplasts and intact cells of TA1 provided evidence that PssN is oriented towards the periplasmic space. Chemical cross-linking of TA1 and E. coli cells overproducing PssN-His(6) protein showed that PssN might exist as a homo-oligomer of at least two monomers. Investigation of the secondary structure of purified PssN-His(6) protein by Fourier transform infrared spectroscopy revealed the predominant presence of P-structure; however, alpha-helices were also detected. Influence of an increased amount of PssN protein on the TA1 phenotype was assessed and correlated with a moderate enhancement of EPS production.

  29. Gabrielska, J. Gagos, M. Gubernator, J. Gruszecki, W. I., Binding of antibiotic amphotericin B to lipid membranes: A H-1 NMR study, Febs Letters, 580(11), 2006, 2677-2685

    Abstract:
    The H-1 NMR technique was applied to study binding of AmB, an antifungal drug, to lipid membranes formed with egg yolk phosphatidylcholine. The analysis of H-1 NMR spectra of liposomes, containing also cholesterol and ergosterol (at 40 mol%), shows that AmB binds preferentially to the polar headgroups. Such a binding restricts molecular motion of the choline fragment in the hydrophilic region at the surface of liposomes but increases the segmental motional freedom in the hydrophobic core. The same effects are also observed in the sterol-containing membranes, except that the effect on the hydrophobic core was exclusively observed in the membranes containing ergosterol. (c) 2006 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

  30. Gruszecki, W. I. Gospodarek, M. Jaskowska, A. Spiewla, E., Adaptation of the photosynthetic apparatus of Nitellopsis obtusa to changing light intensity at the molecular level: different pathways of a singlet excitation quenching, Acta Physiologiae Plantarum, 28(2), 2006, 127-136

    Abstract:
    The effect of prolonged illumination (60 min) with photosynthetically active monochromatic radiation of low intensity (3 mu mol center dot m(-2)center dot s(-1)) and high intensity (60 mu mol center dot m(-2)center dot s(-1)), corresponding to the physiological conditions and light stress conditions, respectively, was Studied in the algae Nitellopsis obtusa. Illumination of Nitellopsis obtusa cells with strong light was associated with activation of the xanthophyll cycle, manifested by the deepoxidation of violaxanthin and accumulation of antheraxanthin and zeaxanthin. At the same time, the efficient singlet excitation quenching in the photosynthetic apparatus was activated, as demonstrated by the decrease in the intensity of the chlorophyll a fluorescence emission by ca 50%. The difference of the fluorescence excitation spectra recorded before and after the light treatment match the difference absorption spectrum of the xanthophyll cycle pigments. The illumination with low light intensity resulted also in the chlorophyll a fluorescence quenching but the effect was very small (less than 10 %). The fluorescence quenching is interpreted in terms of the energy transfer between the Q(y) energy level of chlorophyll a and the 2(1) A(g)(-) energy level of zeaxanthin. The singlet energy levels of carotenoids, corresponding to the green spectral region, are also taken into consideration in the interpretation of the excitation energy exchange between the carotenoids and activation of the strong and the weak excitation quenching, including violaxanthin isomerization, and possible physiological functions of such pathways of energy transfer are discussed.

  31. Gagos, M. Gabrielska, J. Dalla Serra, M. Gruszecki, W. I., Binding of antibiotic amphotericin B to lipid membranes: monomolecular layer technique and linear dichroism-FTIR studies, Molecular Membrane Biology, 22(5), 2005, 433-442

    Abstract:
    Amphotericin B (AmB) is one of the main antibiotics applied in treatment of deep-seated mycotic infections. Tensiometric technique has been applied to monitor binding of AmB, from the water subphase, to the lipid monomolecular layers, formed with dipalmitoylphosphatidylcholine at the air-water interface. Time dependencies of surface pressure in the monolayers demonstrate strong enhancement of AmB binding to monolayers brought about by sterols present in the membranes. The monolayers have been deposited to a solid support and examined by means of FTIR spectroscopy. FTIR measurements show that majority of the AmB molecules which bind to the membranes are localized in the polar headgroup region. The results of the linear dichroism- FTIR measurements are consistent with the microscopic picture according to which the molecules of the membrane-bound AmB are distributed among two orientational fractions: one horizontal and one vertical with respect to the plane of the membrane (59% versus 41% respectively, in the case of the membrane formed with the pure lipid without sterols). The presence of cholesterol in the membranes (50 mol% with respect to lipid) slightly affects such a distribution (53% horizontal versus 47% vertical) but the presence of ergosterol has a pronounced effect in the increase in population of the fraction of horizontally bound AmB (85% horizontal vs. 15% vertical). The results of the measurements indicate that mode of action of the AmB consists in disruption of the polar headgroup region of biomembranes, brought about by the AmB molecules bound horizontally with respect to the plane of the membrane.

  32. Milanowska, J. Gruszecki, W. I., Heat-induced and light-induced isomerization of the xanthophyll pigment zeaxanthin, Journal of Photochemistry and Photobiology B-Biology, 80(3), 2005, 178-186

    Abstract:
    Zeaxanthin is a xanthophyll pigment that plays important physiological functions both in the plant and in the animal kingdom. All-trans is a stereochemical conformation of zeaxanthin reported as specific for the thylakoid membranes of the photosynthetic apparatus and the retina of an eye. On the other hand, the pigment is subjected, in natural environment, to the conditions that promote stereochemical isomerization, such as illumination and elevated temperature. In the present work. the light-induced and heat-induced (the temperature range 35-95 degrees C) isomerization of all-trans zeaxanthin in organic solvent environment hits been analyzed by means of the HPLC technique. The 13-cis conformation has been identified as a major one among the isomerization products. The activation energy of the all-trans to 13-cis isomerization has been determined as 83 +/- 4 kJ/mol and the activation energy of the back reaction as 30 +/- 7 kJ/mol. The reaction of isomerization of the all-trans zeaxanthin at 25 degrees C was substantially more efficient upon illumination. Four different wavelengths of light have been selected for photo-isomerization experiments: 450, 540. 580 and 670 rim, corresponding to the electronic transitions of zeaxanthin from the ground state to the singlet excited states: 1(1) B-u(+), 3(1)A(g)(-), 1(1)B(u)(-) and 2(1)A(g)(-), respectively. The quantum efficiency of the all- trans zeuxanthin isomerization induced by light at different wavelengths: 450, 540, 580 and 670 nm was found to differ considerably and was in the ratio as 1: 15:160:29. The sequence of the quantum efficiency values suggests that the carotenoid triplet state 1(3)B(u), Populated via the internal conversion from the I(3)A(g) triplet state which is generated by the intersystem crossing from the 1(1)B(u)(-) state may be involved in the light-induced isomerization. A physiological importance of the isomerization of zeaxanthin in the retina of an eye, photosynthetic apparatus and of the pigment active as a blue light photoreceptor in stomata is briefly discussed. (c) 2005 Elsevier B.V. All rights reserved.

  33. Herec, M. Dziubinska, H. Trebacz, K. Morzycki, J. W. Gruszecki, W. I., An effect of antibiotic amphotericin B on ion transport across model lipid membranes and tonoplast membranes, Biochemical Pharmacology, 70(5), 2005, 668-675

    Abstract:
    A pH sensitive fluorescence probe piranine trisulfonate, entrapped inside small unilamellar liposomes formed with egg yolk phosphatidylcholine, was applied to investigate effect of polyene antibiotic amphotericin B (AmB) on proton transport across lipid membranes. Time dependencies of fluorescence- monitored pH changes inside lipid vesicles, upon sudden acidification of the liposome suspension, were analyzed in terms of two-exponential kinetics. It appears that addition of AmB at 3 mol%, with respect to lipid, considerably increases the rate constant of the fast component of proton transport (a change from (60 to 149) x 10(-3) s(-1)) and decreases the rate constant of the slow component (a change from (11 to 5) x 10(- 3) s(-1)). Incorporation of 0.1 mol% AmB results in the decrease of both parameters (to (33 and 2) x 10(-3) s(-1), respectively). The increase in the rate of proton transfer across the lipid membrane is interpreted as related to the formation of membrane channels by AmB, at higher concentration of the drug or nonspecific destabilization of the membrane structure. At low concentrations, at which formation of molecular structures of AmB is not possible, the antibiotic molecules are oriented horizontally with respect to the plane of the membrane and act in making the membrane more compact and less permeable to ions. The presence of sterols (cholesterol, ergosterol and cholesterol dimer) in the lipid phase, in the concentration 3 mol% and lower, decreased the rate constants of proton transfer across the membranes but did not influence significantly the effect of AmB on the ion transport. The presence of AmB in the bathing solutions of tonoplast membranes isolated from Conocephalum conicum at the concentrations range 1 x 10(-7) to 3.6 x 10(-5) does not influence considerably the ion current, as monitored by means of the patch-clamp technique. (c) 2005 Elsevier Inc. All rights reserved.

  34. Gagos, M. Menestrina, G. Niewiadomy, A. Gruszecki, W. I., Molecular organization of the antifungal and anticancer drug 2- (2,4-dihydroxyphenylo)-5,6-dichlorobenzothiazole in solution and in monolayers: An effect of pH, Journal of Photochemistry and Photobiology B-Biology, 80(2), 2005, 101-106

    Abstract:
    2-(2,4-Dihydroxyphenylo)-5,6-dichlorobenzothiazol (dHBBT) is a new anticancer, antifungal and antibacterial drug characterised also by cytostatic and anticancer activity. The effect of pH on the molecular organization of dHBBT in monomolecular layers and in solution has been studied by electronic absorption and FT-IR spectroscopies. The analysis of the spectroscopic data suggests that at neutral and at high pH values (pH 6-8) dHBBT appears in the anionic form that prevents the formation of dimers due to the electrostatic repulsion between the molecules. (c) 2005 Elsevier B.V. All rights reserved.

  35. Gruszecki, W. I. Strzalka, K., Carotenoids as modulators of lipid membrane physical properties, Biochimica Et Biophysica Acta-Molecular Basis of Disease, 1740(2), 2005, 108-115

    Abstract:
    Carotenoids are a group of pigments present both in the plant and animal kingdoms, which play several important physiological functions. The protection against active oxygen species, realised via the quenching of excited states of photosensitising molecules, quenching of singlet oxygen and scavenging of free radicals, is one of the main biological functions of carotenoids. Several recent research indicate that the protection of biomembranes against oxidative damage can be also realised via the modification of the physical properties of the lipid phase of the membranes. This work presents an overview of research on an effect of carotenoids on the structural and dynamic properties of lipid membranes carried out with the application of different techniques such as Electron Paramagnetic Resonance, Nuclear Magnetic Resonance, Differential Scanning Calorimetry, X-ray diffractornetry, monomolecular layer technique and other techniques. It appears that, in most cases, polar carotenoids span lipid bilayer and have their polar groups anchored in the opposite polar zones of the membrane. Owing to the van der Waals interactions of rigid rod-like molecules of carotenoid and acyl chains of lipids, pigment molecules rigidify the fluid phase of the membranes and limit oxygen penetration to the hydrophobic membrane core susceptible to oxidative degradation. (c) 2004 Elsevier B.V. All rights reserved.

  36. Gruszecki, W. I. Stiel, H. Niedzwiedzki, D. Beck, A. Milanowska, J. Lokstein, H. Leupold, D., Towards elucidating the energy of the first excited singlet state of xanthophyll cycle pigments by X-ray absorption spectroscopy, Biochimica Et Biophysica Acta-Bioenergetics, 1708(1), 2005, 102-107

    Abstract:
    The first excited singlet state (S-1) of carotenoids (also termed 2A(g)(-)) plays a key role in photosynthetic excitation energy transfer due to its close proximity to the S, (Q,,) level of chlorophylls. The determination of carotenoid 2A(g)(-) energies by optical techniques is difficult; transitions from the ground state (S-0, 1A(g)(-)) to the 2A(g)(-) state are forbidden ("optically dark") due to parity (g <- // -> g) as well as pseudo-parity selection rules (- <- // -> -). Of particular interest are S-1 energies of the so-called xanthophyll-cycle pigments (violaxanthin, antheraxanthin and zeaxanthin) due to their involvement in photoprotection in plants. Previous determinations of S, energies of violaxanthin and zeaxanthin by different spectroscopic techniques vary considerably. Here we present an alternative approach towards elucidation of the optically dark states of xanthophylls by near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The indication of at least one pi* energy level (about 0.5 eV below the lowest 1B(u)(+) vibronic sublevel) has been found for zeaxanthin. Present limitations and future improvements of NEXAFS to study optically dark states of carotenoids are discussed. NEXAFS combined with simultaneous optical pumping will further aid the investigation of these other-wise hardly accessible states. (c) 2005 Elsevier B.V. All rights reserved.

  37. Niedzwiedzki, D. Krupa, Z. Gruszecki, W. I., Temperature-induced isomerization of violaxanthin in organic solvents and in light-harvesting complex II, Journal of Photochemistry and Photobiology B-Biology, 78(2), 2005, 109-114

    Abstract:
    Three main xanthophyll pigments are bound to the major photosynthetic pigment-protein complex of Photosystem 11 (LHCII): lutein, neoxanthin and violaxanthin. Chromatographic analysis of the xanthophyll fraction of LHCII reveals that lutein appears mainly in the all-trans conformation, neoxanthin in the 9'-cis conformation and major fraction of violaxanthin in the all-trans conformation. Nevertheless, a small fraction of violaxanthin appears always in a cis conformation: 9-cis and 13-cis (approximately 4% and 2% in the darkness, respectively). Illumination of the isolated complex (5 min, 445 nm, 250 mumol m(-2) s(-1)) results in the substantial increase in the concentration of the cis steric conformers of violaxanthin: up to 6% of 9-cis and 4% of 13-cis. Similar effect can be obtained by dark incubation of the same preparation for 30 min at 60 degreesC. Heating-induced isomerization of the all-trans violaxanthin can also be obtained in the organic solvent system but the formation of the 9-cis stereoisomer has not been observed under such conditions. The fact that the appearance of the 9-cis form of violaxanthin is specific for the protein environment suggests that violaxanthin may replace neoxanthin in LHCII in the NI xanthophyll binding pocket and that the protein stabilizes this particular conformation. The analysis of the electronic absorption spectra of LHCII and the FTIR spectra of the protein in the Amid I band spectral region indicates that violaxanthin isomerization is associated with the disaggregation of the complex. It is postulated that this reorganization of LHCII provides conditions for desorption of violaxanthin from the pigment protein complexes, its diffusion within the thylakoid membrane and therefore, availability to the enzymatic deepoxidation within the xanthophyll cycle. It is also possible that violaxanthin isomerization plays the role of a security valve, by consuming an energy of excessive excitations in the antenna pigment network (in particular, exchanged at the triplet state levels). (C) 2004 Elsevier B.V. All rights reserved.

  38. Gagos, M. Niewiadomy, A. Gruszecki, W. I., Molecular organization of the antifungal and anticancer drug 2- (2,4-dihydroxyphenylo)-5,6-dichlorobenzothiazole (dHBBT) in solution and in lipid membranes studied by means of electronic absorption spectroscopy, Journal of Photochemistry and Photobiology B-Biology, 76(1-3), 2004, 33-40

    Abstract:
    2-(2,4-Dihydroxyphenylo)-5,6-dichlorobenzthiazole (dHBBT) is a new drug from the group of chemical compounds characterized by documented antifungal, antibacterial, cytostatic as well as antitumour activity. Despite general knowledge regarding pharmacological importance of dHBBT its interaction to biomembranes has not been investigated. In this work, we present the electronic absorption spectroscopic study on molecular organization of dHBBT in organic solvents and on its localization and molecular organization within model lipid membranes formed with dipalmitoylphosphatidylcholine (DPPC). The spectroscopic measurements are interpreted within the framework of the exciton splitting theory. It is concluded that complex absorption spectrum of dHBBT both in the organic solvents and incorporated to DPPC represents superposition of two spectral forms: representing monomers and hypsochromically shifted spectrum representing molecular dimers. Analysis of the temperature dependencies of the absorption spectra of dHBBT incorporated to DPPC liposomes suggests localization of the drug in the polar head-group region of the membrane or in the region of the polar-nonpolar interface. Linear dichroism measurements of dHBBT incorporated to DPPC multibilayers reveal roughly vertical orientation of the drug molecules with respect to the plane of the membrane. A model is presented of molecular organization of dHBBT in lipid membranes. Potential effects of dHBBT on membrane physical properties is briefly discussed. (C) 2004 Elsevier B.V. All rights reserved.

  39. Iwaszko, E. Wardak, A. Krupa, Z. Gruszecki, W. I., Ion transport across model lipid membranes containing light- harvesting complex II: an effect of light, Journal of Photochemistry and Photobiology B-Biology, 74(1), 2004, 13-21

    Abstract:
    The effect of light on proton transport across lipid membranes of small unilamellar liposomes containing incorporated major light-harvesting pigment-protein complex of Photosystem II (LHCII) has been studied with the application of pH-sensitive dyes entrapped inside vesicles. Proton permeability coefficient for LHCII-modified membranes was found to be about twice as high as in the case of the control pure lipid vesicles. Illumination of the samples with light absorbed by the LHCII- bound photosynthetic pigments considerably affects the kinetics of proton transport: it increases the rate and decreases the steady-state level of proton gradient across the membranes. The effect was interpreted in terms of heat-induced conformational changes of LHCII molecular structures that affect proton buffering capacity of this protein. Both the control and the LHCII-modified lipid membranes have been found to be practically impermeable to Ca++ ions, as demonstrated by fluorescence of liposome-entrapped calcium-sensitive probe calcium crimson. The slight differences in the proton transport across the LHCII-containing membranes under the presence of Ca++ suggest calcium binding to this antenna protein. (C) 2004 Elsevier B.V. All rights reserved.

  40. Milanowska, J. Polit, A. Wasylewski, Z. Gruszecki, W. I., Interaction of isomeric forms of xanthophyll pigment zeaxanthin with dipalmitoylphosphatidylcholine studied in monomolecular layers, Journal of Photochemistry and Photobiology B-Biology, 72(1-3), 2003, 1-9

    Abstract:
    Two-component monomolecular layers were formed with DPPC and two stereoisomers of zeaxanthin 9-cis and 13-cis at the argon- water interface. Very distinct over-additivity which represents affection of a lipid arrangement in the membrane has been observed in the case of zeaxanthin 9-cis (maximum at 20 mol%) but not in the case of zeaxanthin 13-cis. The differences in the organization of the isomers of zeaxanthin-DPPC monolayers are interpreted in terms of the different orientation of both xanthophylls at the interface observed at relatively high surface pressures (>25 mN/m) comparable to the surface pressures of biomembranes. The results are consistent with the model according to which zeaxanthin 9-cis adopts a vertical orientation at the polar-nonpolar interface in contrast to zeaxanthin 13-cis, which is oriented horizontally owing to the fact that it interacts by two hydroxyl groups with the same hydrophobic-hydrophilic interface in the monolayer. The findings are discussed in comparison with the behavior of zeaxanthin in the conformation all-trans in the same system. Zeaxanthin all-trans forms efficiently molecular aggregates in the mixed monolayers in contrast to cis isomers. Circular dichroism measurements show the formation of molecular structures by zeaxanthin 13-cis that are interpreted as dimers. FTIR measurements show that these dimers are stabilized by van der Waals interactions unlike aggregated structures formed by all-trans zeaxanthin that are stabilized by hydrogen bonding. Physiological importance of the differences in aggregation and orientation of stereoisomers of zeaxanthin in lipid environment is discussed. (C) 2003 Elsevier B.V. All rights reserved.

  41. Gruszecki, W. I. Herec, M., Dimers of polyene antibiotic amphotericin B, Journal of Photochemistry and Photobiology B-Biology, 72(1-3), 2003, 103-105

  42. Pawlikowska-Pawlega, B. Gruszecki, W. I. Misiak, L. E. Gawron, A., The study of the quercetin action on human erythrocyte membranes, Biochemical Pharmacology, 66(4), 2003, 605-612

    Abstract:
    Quercetin is a naturally occurring flavonoid that exerts multiple pharmacological effects. In our previous study, we showed that quercetin greatly affects the lipid membrane. In this report, a study of quercetin on human erythrocyte membrane has been performed to determine the influence of this flavonoid on the fluidity and the conformational changes of membrane proteins. An additional aim of the study was to find how quercetin presence affects the resistance of membrane to haemolytic agents. The results showed that incorporation of quercetin into the erythrocyte membranes caused the changes of the partition coefficient of the Tempo spin label between the water and polar head group phases. In the studies, the W/S ratio has been used as a monitor of changes in protein conformation and in the environment within the membrane. It was observed that quercetin caused an increase in protein-protein interactions in human erythrocyte membranes. Haemolytic action of quercetin in the dark was also investigated. This compound showed protective effect against hypotonic haemolysis. However, in the heat-induced haemolysis quercetin caused acceleration of haemolysis. Dark reaction of erythrocyte with quercetin resulted in a shrinkage of the cells and alteration of their shapes. From the results we have concluded that modification of erythrocyte membrane by quercetin proceeds via reaction with membrane lipids and proteins. (C) 2003 Elsevier Inc. All rights reserved.

  43. Gruszecki, W. I. Gagos, M. Herec, M. Kernen, P., Organization of antibiotic amphotericin B in model lipid membranes. A mini review, Cellular & Molecular Biology Letters, 8(1), 2003, 161-170

    Abstract:
    Amphotericin B (Am]3) is a polyene antibiotic frequently applied in the treatment of fungal infections. According to the general understanding, the mode of action of AmB is directly related to the molecular organization of the drug in the lipid environment, in particular to the formation of pore-like molecular aggregates. Electronic absorption and fluorescence techniques were applied to investigate formation of molecular aggregates of AmB in the lipid environment of liposomes and monomolecular layers formed at the argon-water interface. It appears that AmB dimers, stabilized by van der Waals interactions, are present in the membrane environment along with the aggregates formed by a greater number of molecules. Linear dichroism measurements reveal that AmB is distributed between two fractions of molecules, differently oriented with respect to the bilayer. Molecules in one fraction remain parallel to the plane of the membrane and molecules in the other one are perpendicular. Scanning Force Microscopy imaging of the surface topography of the monolayers formed with AmB in the presence of lipids reveals formation of pore-like structures characterized by the external diameter close to 17 Angstrom and the internal diameter close to 6 Angstrom. All the findings are discussed in terms of importance of the molecular organization of AmB in the pharmacological action, as well as of the toxic side effects of the drug.

  44. Niedzwiedzki, D. Gruszecki, W. I., Interaction between chlorophyll a and violaxanthin in different steric conformations - Model studies in monomolecular layers, Colloids and Surfaces B-Biointerfaces, 28(1), 2003, 27-38

    Abstract:
    Monomolecular layers of pure chlorophyll a (Chl a), violaxanthin in the conformation all-trans, 9-cis, 13-cis and two-component monomolecular layers formed with Chl a and all isomers of violaxanthin, at a stoichiometric ratio 1: 1, were formed and compressed at the argon-water interface. The specific molecular areas of Chl a and the isomers of violaxanthin in monomolecular layers were determined on the basis of the isotherms of compression. The isotherms of compression of the Chl a -violaxanthin-all trans monolayers correspond well to the theoretical ones, calculated on the basis of the additivity rule. The theoretical isotherms of compression of monolayers formed with Chl a and violaxanthin in conformations 9-cis and 13-cis are shifted towards higher molecular areas with respect to the experimental ones, indicating molecular interaction between components of the system. Monolayers were also deposited to a solid support by means of the Langmuir-Blodgett technique and subjected to spectroscopic studies: to quartz lamella in the case of electronic absorption and fluorescence spectroscopy and to ZnSe crystal in the case of Fourier Transform Infrared Spectroscopy (FTIR). The comparison of the absorption and Chl a fluorescence excitation spectra enabled to make a calculation of the rate of excitation energy transfer from violaxanthin to Chl a. Efficiency of energy transfer from a carotenoid to Chl a was 32% in the case of violaxanthin all-trans, 21% in the case of violaxanthin 9-cis and 15% for violaxanthin 13-cis. Such findings suggest a structural role of violaxanthin in conformation 9-cis and 13-cis and an accessory role of violaxanthin all-trans in the photosynthetic apparatus. The analysis of FTIR spectra reveals molecular interaction between Chl a and violaxanthin in conformations cis via the hydroxyl groups of xanthophylls located in the C3 and C3' positions. (C) 2002 Elsevier Science B.V. All rights reserved.

  45. Gruszecki, W. I. Gagos, M. Herec, M., Dimers of polyene antibiotic amphotericin B detected by means of fluorescence spectroscopy: molecular organization in solution and in lipid membranes, Journal of Photochemistry and Photobiology B-Biology, 69(1), 2003, 49-57

    Abstract:
    Fluorescence emission from amphotericin B dissolved in 2- propanol-water was recorded in the spectral region 500-650 nm. The fluorescence excitation spectrum corresponds to the absorption spectrum of the monomeric drug. The large energy shift between the excitation and emission bands indicates that emission takes place from an energy level different than that responsible for absorption. These levels were attributed to the 2(1)A(g) and 1(1)B(u) states, respectively. Excitation of the same sample with short wavelength radiation (below 350 nm) yields light emission between 400 and 550 nm. The fluorescence excitation spectrum corresponding to this emission band displays distinct maxima at 350, 334 and 318 nm. This band was analyzed in terms of the exciton splitting theory and assigned to amphotericin B in a dimeric form, in which chromophores are spaced by 4.9 Angstrom. The binding energy of the dimers, determined to be 4.9 kJ/mol, indicates that the structures are stabilized by van der Waals interactions. The same type of molecular structures was also detected in the lipid membranes formed with dipalmitoylphosphatidylcholine. Linear dichroism of amphotericin B embedded in lipid multibilayers indicates that molecules are distributed between two fractions: parallel (38%) and perpendicular (62%) with respect to the membrane. The biological importance of such membrane organization is discussed. (C) 2002 Elsevier Science B.V. All fights reserved.

  46. Sujak, A. Mazurek, P. Gruszecki, W. I., Xanthophyll pigments lutein and zeaxanthin in lipid multibilayers formed with dimyristoylphosphatidylcholine, Journal of Photochemistry and Photobiology B-Biology, 68(1), 2002, 39-44

    Abstract:
    This paper reports the research on the effect of two main carotenoid pigments present in the membranes of macula lutea of the vision apparatus of primates, including humans, lutein and zeaxanthin, on the structure of model membranes formed with dimyristoylphosphatidylcholine (DMPC). The effects observed in DMPC are compared to the effects observed in the membranes formed with other phosphatidylcholines (PC): egg yolk PC (EYPC), and dipalmitoyl-PC (DPPC). The analysis has been focused, in particular, on the following aspects of the organization of lipid-carotenoid membranes: aggregation state of pigments, an effect on a thickness of the bilayer and pigment orientation within the membranes. These problems have been addressed with the application of UV-Vis absorption spectroscopy, linear dichroism measurements and the diffractometric technique. (1) Both lutein and zeaxanthin appear in a partially aggregated form in the oriented DMPC multibilayers, even at molar fractions as low as 2 mol.% with respect to lipid. (2) Orientation of the transition dipole of both xanthophylls with respect to the axis normal to the plane of DMPC membrane is different in the case of a monomeric form (34+/-3degrees in the case of lutein and 26+/-3degrees in the case of zeaxanthin) but essentially the same in the case of aggregated forms of both pigments (42+/-3degrees in the case of utein and 40+/-5degrees in the case of zeaxanthin). It was found that only lutein has an effect on the increase in the thickness of the DMPC membranes (by about 3 Angstrom at 25 degreesC). A similar effect was observed also in the case of DPPC at the same temperatures despite the differences in the physical state of both membrane systems. The differences between the effects of lutein and zeaxanthin observed are interpreted in terms of differences of stereochemical structure of both xanthophylls leading to the different localization in the lipid phase. The results demonstrate significant differences in the behavior of lutein and zeaxanthin in model membranes, which may contribute to their different physiological functions and different efficacy as membrane antioxidants. (C) 2002 Elsevier Science BY. All rights reserved.

  47. Gruszecki, W. I. Gagos, M. Kernen, P., Polyene antibiotic amphotericin B in monomolecular layers: spectrophotometric and scanning force microscopic analysis, Febs Letters, 524(1-3), 2002, 92-96

    Abstract:
    Monolayers of amphotericin B (AmB) and monolayers composed of AmB and dipalmitoylphosphatidylcholine (DPPC) were formed at the argon-water interface and deposited on a solid support by means of the Langmuir-Blodgett technique. The hypsochromic shift observed in the absorption spectra of monolayers is indicative of aggregated structures of AmB. The exciton splitting theory allowed us to calculate the distance between neighboring molecules in the aggregates as 7.8. Scanning force microscopy of the AmB monolayers revealed the formation of a homogeneous monolayer composed of molecules separated by a distance of 6-8. Microscopy also reveals the formation of cylindrical structures of AmB with a diameter close to 17 A (internal diameter close to 6) in the monolayers containing additionally 10 mol% DPPC. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.

  48. Grudzinski, W. Krupa, Z. Garstka, M. Maksymiec, W. Swartz, T. E. Gruszecki, W. I., Conformational rearrangements in light-harvesting complex II accompanying light-induced chlorophyll a fluorescence quenching, Biochimica Et Biophysica Acta-Bioenergetics, 1554(1-2), 2002, 108-117

    Abstract:
    Light-induced chlorophyll a (Chl a) fluorescence quenching was studied in light-harvesting complex of photosystem II (LHCII). Fluorescence intensity decreased by ca. 20% in the course of 20 min illumination (412 nm, 36 mumol m(-2) s(-1)) and was totally reversible within 30 min dark adaptation. The pronounced quenching was observed only in LHCII in an aggregated form and exclusively in the presence of molecular oxygen. Structural rearrangement of LHCII correlated to the quenching was monitored by measuring changes in UV-Visible light absorption spectra, and by measuring Fourier-transform infrared spectroscopy (FTIR) in the Amide I region of the protein (1600- 1700 cm(-1)). The light-induced structural rearrangement of LHCII was interpreted as a partial disaggregation of the complex based on the decrease in the light scattering signal and the characteristic features observed in the FTIR spectra: the relative increase in the intensity of the band at 1653 cm(- 1), corresponding to a protein in the a-helical structure at the expense of the band centered at 1621 cm(-1), characteristic of aggregated forms. The fact that the light-driven isomerization of the all-tracts violaxanthin to the 13-cis form was not observed under the non-oxygenic conditions coincided with the lack of large-scale conformational reorganization of LHCII. The kinetics of this large-scale structural effect does not correspond to the light-induced fluorescence quenching, in contrast to the kinetics of structural changes in LHCII observable at low oxygen concentrations. Photo-conversion of 5% of the pool of all-trans violaxanthin to 9-cis isomer was observed under such conditions. Possible involvement of the violaxanthin isomerization in the process of structural rearrangements and excitation quenching in LHCII is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.

  49. Gruszecki, W. I. Trebacz, K. Iwaszko, E., Application of very small force measurements in monitoring the response of sunflower to weak blue light, Journal of Photochemistry and Photobiology B-Biology, 66(2), 2002, 141-147

    Abstract:
    A diaheliotropic response of sunflower, Helianthus annuus, following a short pulse of low intensity blue light to a small area of leaf surface was examined with the application of the very low-force-measurements technique (the order of magnitude of 10(-5).N). One leaf from a pair was illuminated with a low intensity blue-light-pulse and the force was recorded, generated by the stem of the plant tending to bend. A very low phototropic effect in response to blue light alone was observed which could be considerably enhanced by the application of background illumination with red light. Microelectrode measurements of the membrane potential of the mesophyll cells of the sunflower leaf showed hyperpolarization in response to a blue light pulse, observed very clearly under application of the red light background illumination. The hyperpolarization of the membrane potential was accompanied by acidification of extracellular compartments as monitored with a miniature pH- sensitive electrode, placed in the epidermis of the stem. The relatively short lag period between the hyperpolarization of the membrane potential and the decrease in pH suggests that the hyperpolarization is a direct effect of the blue light-induced proton extrusion. The acidification correlates with the light response, which suggests that acidification-induced stem wall loosening is responsible for the blue light-induced bending. The examined mechanisms are discussed in terms of sun tracking by a sunflower. (C) 2002 Elsevier Science BY All rights reserved.

  50. Gagos, M. Koper, R. Gruszecki, W. I., Spectrophotometric analysis of organisation of dipalmitoylphosphatidylcholine bilayers containing the polyene antibiotic amphotericin B, Biochimica Et Biophysica Acta-Biomembranes, 1511(1), 2001, 90-98

    Abstract:
    Amphotericin B (AmB) is a polyene antibiotic widely used in the treatment of deep-seated fungal infections. The mode of action of AmB is directly related to the effect of the drug on the lipid phase of biomembranes. In the present work the effect of AmB on the properties of lipid bilayers formed with dipalmitoylphosphatidylcholine (DPPC) and the effect of the lipid phase on the molecular organisation of AmB were studied with application of spectrophotometry in the UV-Vis region. The absorption spectra of AmB in lipid membranes display a complex structure with hypsochromically and bathochromically shifted bands indicative of formation of molecular aggregates of the drug. Formation of molecular aggregates was analysed at different concentrations of the drug in the lipid phase in the range 0.05-5 mol% and at different temperatures in the range 5- 55 degreesC, The aggregation level of AmB in the ordered phase of DPPC displayed a minimum corresponding to a concentration of 1 mol% with respect to the lipid. An increase in the aggregation level was observed in the temperature region corresponding to the main phase transition. The structure of molecular aggregates of AmB is analysed on the basis of spectroscopic effects in terms of the exciton splitting model. Analysis of the position of the absorption maximum of AmB in the lipid phase of DPPC in terms of the theory of solvatochrome effects makes it possible to ascribe the refractive indices n = 1.40 and n = 1.49 to the hydrophobic core of the membrane in the L-alpha and the P-beta' phase respectively. Analysis of the aggregation of AmB in the lipid phase in relation to the physical state of the membrane reveals that the temperature range of the main phase transition of a lipid cluster in the immediate vicinity of AmB depends on its concentration. The termination of the phase transition temperature, as read from the AmB aggregation, varies between 42 degreesC at 1 mol% AmB in DPPC and 49 degreesC at 5 mol% AmB in DPPC. The exciton splitting theory applied to the analysis of the spectroscopic data makes it possible to calculate the diameter of the AmB pore as 2.8 Angstrom in the gel phase and 3.6 Angstrom in the fluid phase of the DPPC membrane, on the assumption that the pore is formed by nine AmB molecules. (C) 2001 Elsevier Science B.V. All rights reserved.

  51. Grudzinski, W. Matula, M. Sielewiesiuk, J. Kernen, P. Krupa, Z. Gruszecki, W. I., Effect of 13-cis violaxanthin on organization of light harvesting complex II in monomolecular layers, Biochimica Et Biophysica Acta-Bioenergetics, 1503(3), 2001, 291-302

    Abstract:
    Lutein, neoxanthin and violaxanthin are the main xanthophyll pigment constituents of the largest light-harvesting pigment- protein complex of photosystem II (LHCII). High performance liquid chromatography analysis revealed photoisomerization of LHCII-bound violaxanthin from the conformation all-trans to the conformation 13-cis and 9-cis. Maximally, the conversion of 15% of all-trans violaxanthin to a cis form could be achieved owing to the light-driven reactions. The reactions were dark- reversible. The all-trans to cis isomerization was found to be driven by blue light, absorbed by chlorophylls and carotenoids, as well as by red light, absorbed exclusively by chlorophyll pigments. This suggests that the photoisomerization is a carotenoid triplet-sensitized reaction. The monomolecular layer technique was applied to study the effect of the 13-cis conformer of violaxanthin and its de-epoxidized form, zeaxanthin, on the organization of LHCII as compared to the all-trans stereoisomers. The specific molecular areas of LHCII in the two-component system composed of protein and exogenous 13-cis violaxanthin or 13-cis zeaxanthin show overadditivity, which is an indication of the xanthophyll-induced disassembly of the aggregated forms of the protein. Such an effect was not observed in the monomolecular layers of LHCII containing all- trans conformers of violaxanthin and zeaxanthin. 77 K chlorophyll a fluorescence emission spectra recorded from the Langmuir-Blodgett (L-B) films deposited to quartz from monomolecular layers formed with LHCII and LHCII in the two- component systems with all-trans and 13-cis isomers of violaxanthin and zeaxanthin revealed opposite effects of both conformers on the aggregation of the protein. The cis isomers of both xanthophylls were found to decrease the aggregation level of LHCII and the all-trans isomers increased the aggregation level. The calculated efficiency of excitation energy transfer to chlorophyll a from violaxanthin assumed to remain in two steric conformations was analyzed on the basis of the chlorophyll a fluorescence excitation spectra and the mean orientation of violaxanthin molecules in LHCII (71 degrees with respect to the normal to the membrane), determined recently in the linear dichroism experiments [Gruszecki et al., Biochim. Biophys. Acta 1412 (1999) 173-183]. The calculated efficiency of excitation energy transfer from the violaxanthin pool assumed to remain in conformation all-trans was found to be almost independent on the orientation angle within a variability range. In contrast the calculated efficiency of energy transfer from the form cis was found to be strongly dependent on the orientation and varied between 1.0 (at 67.48 degrees) and 0 (at 70.89 degrees). This is consistent with two essentially different, possible functions of the cis forms of violaxanthin: as a highly efficient excitation donor (and possibly energy transmitter between other chromophores) or purely as a LHCII structure modifier. (C) 2001 Elsevier Science B.V. All rights reserved.

  52. Sujak, A. Gruszecki, W. I., Organization of mixed monomolecular layers formed with the xanthophyll pigments lutein or zeaxanthin and dipalmitoylphosphatidylcholine at the argon-water interface, Journal of Photochemistry and Photobiology B-Biology, 59(1-3), 2000, 42-47

    Abstract:
    Two-component monomolecular layers were formed with two xanthophyll pigments, lutein and zeaxanthin and dipalmitoylphosphatidylcholine (DPPC), at the argon-water interface. Analysis of the mean molecular area parameters versus molar fraction of the xanthophyll component shows large overadditivity (ca. 50 Angstrom (2) in the case of zeaxanthin and 150 Angstrom (2) in the case of lutein) in the region of low molar fractions of carotenoids (maximum at 5 mol% in the case of zeaxanthin and at 20 mol% in the case of lutein). The experimental values of a mean molecular area are in good agreement with the values expected, based on the additivity rule at high molar percentages of the xanthophylls. Absorption spectroscopy of a single monolayer at the argon-water interface in the UV-Vis region has also been applied to analyze the formation of molecular assemblies of lutein in monomolecular films. The differences in the organization of lutein-DPPC and zeaxanthin-DPPC monolayers are interpreted in terms of the aggregation of xanthophyll pigments in the layers and different orientation of both xanthophylls at the interface. The results are discussed in relation to possible physiological functions of lutein and zeaxanthin in the membranes of the retina of an eye. (C) 2000 Elsevier Science B.V. All rights reserved.

  53. Okulski, W. Sujak, A. Gruszecki, W. I., Dipalmitoylphosphatidylcholine membranes modified with zeaxanthin: numeric study of membrane organisation, Biochimica Et Biophysica Acta-Biomembranes, 1509(1-2), 2000, 216-228

    Abstract:
    The model of a dipalmitoylphosphatidylcholine (DPPC) bilayer containing a xanthophyll pigment zeaxanthin (ZEA) is proposed. The model is based on the ten-state Pink-Green-Chapman model of a lipid monolayer. The Monte Carlo method of computer simulation has been applied. Our model of the lipid membrane consists of two lipid monolayers with ZEA molecules spanning the lipid bilayer. The concentration of ZEA molecules is assumed to be conserved. Within the model, the interactions between lipid monolayers in a bilayer exist through ZEA molecules only. The experimental data concerning the aggregation of ZEA in DPPC from the literature and from our research were applied as a criterion to fit the model parameters. The model gives the dependences of the main phase transition temperature on ZEA/DPPC molar ratio, the percentage of ZEA in a monomeric form on ZEA/DPPC molar ratio and on temperature. The dependences obtained within the model and the experimental ones are in qualitative agreement. The influence of intermolecular interaction parameters on ZEA aggregation has been discussed. The differences between the model and the experimental results concerning mainly the pattern of ZEA aggregation have been discussed. Analyses of the lipid microconfiguration allow to advance the hypothesis concerning the influence of ZEA on the membrane permeability. (C) 2000 Elsevier Science B.V. All rights reserved.

  54. Sujak, A. Okulski, W. Gruszecki, W. I., Organisation of xanthophyll pigments lutein and zeaxanthin in lipid membranes formed with dipalmitoylphosphatidylcholine, Biochimica Et Biophysica Acta-Biomembranes, 1509(1-2), 2000, 255-263

    Abstract:
    Carotenoid pigments and in particular xanthophylls play several physiological functions in plant and animal membranes. Xanthophylls are present in biological membranes in the form of pigment-protein complexes but also as direct components of lipid phase. The biological activity of carotenoids in membranes depends on a molecular organisation of pigments in lipid bilayers, in particular the localisation, orientation and aggregational state. In the present work the organisation of lutein- and zeaxanthin-containing lipid membranes was analysed with the application of electronic absorption spectroscopy. Both xanthophyll pigments incorporated to the dipalmitoylphosphatidylcholine (DPPC) unilamellar liposomes form I-I-type molecular aggregates, manifested by the hypsochromic shift of the main absorption band of carotenoids. The aggregation of lutein and zeaxanthin in DPPC membranes was observed even at relatively low concentrations of a pigment in the lipid phase (1-5 mol%). Gaussian analysis of the absorption spectra of lutein and zeaxanthin in DPPC membranes in terms of the exciton splitting theory revealed the formation of different molecular structures of pigments interpreted as dimers, trimers, tetramers and large aggregates. The fraction of lutein and zeaxanthin in the monomeric form was found to depend on the physical state of the lipid phase. Pronounced monomerisation of lutein and zeaxanthin was observed as accompanying the transition from the P-beta' phase to the L- alpha phase of DPPC, mostly at the expense of the trimeric and tetrameric forms. The fraction of monomers of lutein is always lower by 10-30% than that of zeaxanthin under the same experimental conditions. Different organisational forms of lutein and zeaxanthin in the model system studied are discussed in terms of possible physiological functions of these pigments in the membranes of the retina: zeaxanthin in the protection of the lipid phase against oxidative damage and lutein in absorbing short wavelength radiation penetrating retina membranes. (C) 2000 Elsevier Science B.V. All rights reserved.

  55. Gruszecki, W. I. Zelent, B. Tajmir-Riahi, H. A. Wang, G. M. Taleb, T. Veeranjaneyulu, K. Leblanc, R. M., Chlorophyll a-violaxanthin interactions in monolayers at air- water interface and in Langmuir-Blodgett films, Colloids and Surfaces B-Biointerfaces, 19(2), 2000, 117-125

    Abstract:
    Short distance interactions of chlorophyll a with violaxanthin (Viol) were studied in monolayers at the air-water interface and in Langmuir-Blodgett films. The surface pressure-area (pi- A) isotherms for Chl a, Viol, and Chl a-Viol mixtures clearly indicate the formation of two types of complexes between Chi a and Viol with the stoichiometric ratios of 2:1 and 1:1. The complexes formed between Chi a and Viol are reflected by the changes in molecular organization of Viol in monolayers. As the fluorescence properties of Chi a molecules are known to be strongly dependent on changes in the degree of its aggregation, we followed the changes in fluorescence at different molar ratios. The molecular aggregations are noticed by the changes in band intensities at 683 and 730 nm in fluorescence emission spectra and an increase in the relative intensity of fluorescence short lifetime component of Chi a. Chi a-Viol interactions in monolayers were also made clear by the analysis of the shortwave region of the photoacoustic spectra explaining very efficient singlet-singlet excitation energy transfer from caratenoid to Chi a. Further, Chi a-Viol interactions and modeling of the formation of the complexes were also discussed based on the FTIR spectra of pure components as well as mixed systems. (C) 2000 Elsevier Science B.V. All rights reserved.

  56. Janas, T. Nowotarski, K. Gruszecki, W. I. Janas, T., The effect of hexadecaprenol on molecular organisation and transport properties of model membranes, Acta Biochimica Polonica, 47(3), 2000, 661-673

    Abstract:
    The Langmuir monolayer technique and voltammetric analysis were used to investigate the properties of model lipid membranes prepared from dioleoylphosphatidylcholine (DOPC), hexadecaprenol (C-80), 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.

  57. Wardak, A. Brodowski, R. Krupa, Z. Gruszecki, W. I., Effect of light-harvesting complex II on ion transport across model lipid membranes, Journal of Photochemistry and Photobiology B-Biology, 56(1), 2000, 12-18

    Abstract:
    The effect of the incorporation of the major Light-harvesting complex of photosystem II (LHCII) to planar bilayer lipid membranes (BLMs) formed from soybean asolectin and unilamellar small liposomes formed from egg-yolk phosphatidylcholine on ion transport across the lipid bilayer has been studied. The specific conductivity of the BLM rises from 5.2+/-0.8x10(-9) up to 510x10(-9) O(-1)cm(-2) upon the incorporation of LHCII. The conductivity of the membrane with LHCII depends upon the ionic strength of the bathing solution and is higher by a factor of five when the KCI concentration increases from 0.02 to 0.22 M. Such a strong effect has not been observed in the same system without LHCII. The liposome model is also applied to analyse the effect of LHCII on the bilayer permeability to protons. Unilamellar liposomes with a diameter less than 50 nm have been prepared, containing (trapped inside) Neutral Red, a pigment sensitive to proton concentration. A gradient of protons on the membrane is generated by the acidification of the liposome suspension and spectral changes of Neutral Red are recorded in time, reflecting the penetration of protons into the internal space of liposomes. Two components of proton permeation across Liposome membranes are observed: a fast one (proceeding within seconds) and a slow one (operating on the time scale of minutes). The rate of both components of proton transport across LHCII-containing membranes is higher than for liposomes alone. The enhancement effect of LHCII on the ion transport across the lipid membrane is discussed in terms of aggregation of the pigment-protein complexes. The possible physiological importance of such an effect in controlling ion permeability across the thylakoid membrane is discussed. (C) 2000 Elsevier Science S.A. All rights reserved.

  58. Sujak, A. Gabrielska, J. Grudzinski, W. Borc, R. Mazurek, P. Gruszecki, W. I., Lutein and zeaxanthin as protectors of lipid membranes against oxidative damage: The structural aspects, Archives of Biochemistry and Biophysics, 371(2), 1999, 301-307

    Abstract:
    Two main xanthophyll pigments are present in the membranes of macula lutea of the vision apparatus of primates, including humans: lutein and zeaxanthin. Protection against oxidative damage of the lipid matrix and screening against excess radiation are the most likely physiological functions of these xanthophyll pigments in macular membranes, A protective effect of lutein and zeaxanthin against oxidative damage of egg yolk lecithin liposomal membranes induced by exposure to UV radiation and incubation with 2,2'-azobis (2- methypropionamidine) dihydrochloride, a water-soluble peroxidation initiator, was studied. Both lutein and zeaxanthin were found to protect lipid membranes against free radical attack with almost the same efficacy. The W-induced lipid oxidation was also slowed down by lutein and zeaxanthin to a very similar rate in the initial stage of the experiments (5-15 min illumination) but zeaxanthin appeared to be a better photoprotector during the prolonged UV exposure, The decrease in time of a protective efficacy of lutein was attributed to the photooxidation of the carotenoid itself. Both lutein and zeaxanthin were found to slightly modify mechanical properties of the liposomes in a very similar fashion as concluded on the basis of H-1 NMR and diffractometric measurements of pure egg yolk membranes and membranes pigmented with the xanthophylls. Linear dichroism analysis of the mean orientation of the dipole transition moment of the xanthophylls incorporated to the lipid multibilayers revealed essentially different orientation of zeaxanthin and lutein in the membranes, Zeaxanthin was found to adopt roughly vertical orientation with respect to the plane of the membrane. The relatively large orientation angle between the transition dipole and the axis normal to the plane of the membrane found in the case of lutein (6 degrees in the case of 2 mol% lutein in EYPC membranes) was interpreted as a representation of the existence of two orthogonally oriented pools of lutein, one following the orientation of zeaxanthin and the second parallel with respect to the plane of the membrane, The differences in the protective efficacy of lutein and zeaxanthin in lipid membranes were attributed to a different organization of zeaxanthin-lipid and lutein-lipid membranes. (C) 1999 Academic Press.

  59. Gruszecki, W. I. Sujak, A. Strzalka, K. Radunz, A. Schmid, G. H., Organisation of xanthophyll-lipid membranes studied by means of specific pigment antisera, spectrophotometry and monomolecular layer technique lutein versus zeaxanthin, Zeitschrift Fur Naturforschung C-a Journal of Biosciences, 54(7-8), 1999, 517-525

    Abstract:
    The structure of the xanthophyll pigments lutein and zeaxanthin differs in the position of one double bond and refers to one of the ionon rings. Specific antibodies to zeaxanthin were used to analyse the localisation and orientation of these two xanthophyll pigments in lipid membranes formed with egg yolk lecithin. Bimolecular and monomolecular layers were used. Antibody-antigen interaction was demonstrated and analysed by the bathochromic shift of the absorption spectra of both pigments and by the increase of light-scattering of the pigmented liposome suspension. It appeared that the extent of the spectral effects accompanying the interaction of the antiserum to zeaxanthin, injected to the liposome suspension which was pigmented with either zeaxanthin or lutein, was different in spite of their similar molecular structures. The results are interpreted in terms of a localisation and distribution of lutein, in the hydrophobic phase of liposomes within two essentially different pigment pools, one oriented horizontally and the other vertically with respect to the membrane plane. This interpretation is supported by the analysis of isotherms of the compression of monomolecular layers of lutein and zeaxanthin formed at the air-water interface and of mixed xanthophyll-lipid monolayers as well as by analysis of the penetration of antibody proteins dissolved in the subphase into the mixed xanthophyll-lipid films.

  60. Gruszecki, W. I. Grudzinski, W. Matula, M. Kernen, P. Krupa, Z., Light-induced excitation quenching and structural transition in light-harvesting complex II, Photosynthesis Research, 59(2-3), 1999, 175-185

    Abstract:
    Light-induced fluorescence quenching of chlorophyll a in light- harvesting complex II (LHCII) incorporated into liposomes was examined. The rate of fluorescence quenching was found to depend on the incubation temperature. The effect was almost not observed at liquid nitrogen temperature, demonstrated a lag phase after onset of light at temperatures below 25 degrees C and was most distinctly pronounced at temperatures above 25 degrees C. Energetic uncoupling of accessory xanthophylls and chlorophyll a, and energetic uncoupling of chlorophyll b and chlorophyll a were observed as accompanying the excitation quenching. The observed changes were reversible during dark incubation. Similar energetic uncoupling was also observed in darkness, induced by the increase in temperature. Additionally, the temperature characteristics of fluorescence measurements displayed a pronounced transition in the region of 22-25 degrees C. The experiments carried out with the monomolecular layer technique indicated a structural transition of LHC II in the same temperature region as demonstrated by an increase in the mean molecular area of LHC II at the argon-water interface. Alterations in surface topography induced by temperature changes could also be observed with scanning force microscopy of LHC II monolayers deposited as Langmuir-Blodgett films onto glass slides. The transition was found to be associated with the enhanced excitation energy consumption by the protein, monitored by calorimetric measurements. It is proposed that the observed transition efficiently protects LHC II against overexcitation-related damage and is therefore of physiological importance.

  61. Gruszecki, W. I. Grudzinski, W. Banaszek-Glos, A. Matula, M. Kernen, P. Krupa, Z. Sielewiesiuk, J., Xanthophyll pigments in light-harvesting complex II in monomolecular layers: localisation, energy transfer and orientation, Biochimica Et Biophysica Acta-Bioenergetics, 1412(2), 1999, 173-183

    Abstract:
    Monomolecular layers of the largest light-harvesting pigment- protein complex of Photosystem II (LHCII) were formed at the argon-water interface. The molecular area of the LHCII monomer in monomolecular layers determined from the isotherms of compression is found to be close to 14 nm(2), which corresponds well to the molecular dimensions of the protein evaluated on the basis of crystallographic studies. Monolayers of LHCII were deposited on a glass support by means of the Langmuir-Blodgett technique and subjected to spectroscopic studies: electronic absorption spectrophotometry and spectrofluorometry. The fluorescence excitation spectra of chlorophyll a in monolayers of LHCII were analysed using gaussian deconvolution, Comparison of the absorption and fluorescence excitation spectra enabled calculation of the rate of excitation energy transfer in the system. Excitation energy was found to be transferred to chlorophyll a from chlorophyll b with 97% efficiency, from neoxanthin with 85%, from lutein with 62% and from violaxanthin with at least 54% efficiency. The analysis of the position of the 0-0 absorption band of the xanthophylls revealed that neoxanthin is located in the same protein environment as lutein but in a different environment than violaxanthin. The analysis of fluorescence excitation spectra of chlorophyll a in LHCII, recorded with the excitation light beam polarised in two orthogonal directions, enabled the determination of the mean orientation angle of the accessory xanthophyll pigments with respect to the plane of the sample. The mean orientation of lutein found in this study (approx. 51 degrees) corresponds well to the crystallographic data. Neoxanthin was found to adopt a similar orientation to lutein. The transition dipole moment of violaxanthin was found to form a mean angle of 71 degrees with the axis spanning two polar regions of the protein, perpendicular to the plane of the monolayer, suggesting planar orientation of this pigment with respect to the plane of the thylakoid membrane. These experimentally determined xanthophyll orientations are discussed in terms of importance of peripheral xanthophyll pigments in supramolecular organisation of LHCII and the operation of the xanthophyll cycle within the thylakoid membrane. (C) 1999 Elsevier Science B.V. All rights reserved.

  62. Kernen, P. Gruszecki, W. I. Matula, M. Wagner, P. Ziegler, U. Krupa, Z., Light-harvesting complex II in monocomponent and mixed lipid- protein monolayers, Biochimica Et Biophysica Acta-Biomembranes, 1373(2), 1998, 289-298

    Abstract:
    Monomolecular layers at the air-water interface were formed directly with isolated largest light-harvesting pigment-protein complex of Photosystem II (LHC II) or out of egg yolk lecithin (EYL) liposomes containing incorporated LHC II. Pure protein monolayers showed a mean area of 1400 Angstrom(2) per molecule at the air-water interface. Monolayers were deposited onto glass slides by means of Langmuir-Blodgett (LB) technique. Chlorophyll fluorescence of LHC II-LB and EYL-LHC II-LB films proved energetic coupling of chlorophyll a and b, thus indicating native conformation of LHC II within the monolayers, Scanning force microscopy (SFM) revealed ring-like structures formed in monocomponent protein layers as well as in mixed protein-lipid films. These results suggest that a structural arrangement of LHC II is favoured in a lipid environment but that the protein has itself a strong tendency for structural complex rearrangement in our system. (C) 1998 Elsevier Science B.V. All rights reserved.

  63. Wojtowicz, K. Gruszecki, W. I. Walicka, M. Barwicz, J., Effect of amphotericin B on dipalmitoylphosphatidylcholine membranes: calorimetry, ultrasound absorption and monolayer technique studies, Biochimica Et Biophysica Acta-Biomembranes, 1373(1), 1998, 220-226

    Abstract:
    Amphotericin B (AmB) is a popular drug frequently applied in the treatment of mycosis. Differential scanning calorimetry (DSC), ultrasound absorption and monomolecular layer technique were applied to study the effect of AmB on organisation of dipalmitoylphosphatidylcholine (DPPC) membranes. DSC-determined enthalpy of the main phase transition of DPPC liposomes was found to be a sensitive parameter to monitor AmB-DPPC interaction. The enthalpy of the phase transition decreases with the increase in molar fraction of AmB incorporated to membranes. The exceptionally sharp decrease in the enthalpy of the, transition was observed in the membranes containing 5-7 mol% AmB. Ultrasound absorption-monitored main phase transition of DPPC is very broad under the presence of 5 mol% AmB showing destabilisation and disorganisation or a membrane structure. These findings are discussed in comparison to monomolecular layer study of two-component DPPC-AmB system. Analysis of the surface pressure-molecular area isotherms of compressing DPPC- AmB films at the air-water interface shows pronounced increase in mean molecular area at AmB concentrations corresponding to those found to destabilise DPPC membranes of liposomes. Disorganisation of lipid bilayers due to the presence of AmB in concentrations below 10 mol% with respect to lipid is discussed in terms of toxicity and side effects of this drug. (C) 1998 Elsevier Science B.V. All rights reserved.

  64. Kernen, P. Gruszecki, W. I. Matula, M. Wagner, P. Ziegler, U. Krupa, Z., Spectroscopic studies and scanning force microscopy of light- harvesting complex II in supported protein and lipid monolayers, Biophysical Journal, 74(2), 1998, A75-A75

  65. Gruszecki, W. I. Wardak, A. Maksymiec, W., The effect of blue light on electron transport in photosystem II reconstituted in planar bilayer lipid membrane, Journal of Photochemistry and Photobiology B-Biology, 39(3), 1997, 265-268

    Abstract:
    Photosystem II particles (PS II) isolated from bean leaves were reconstituted to planar lipid bilayer membranes (BLM). The light-driven electron transport across PS II-BLM has been observed. The direction of the electric current was consistent with the vectorial electron transport within PS II, i.e. between water and exogenous electron acceptor ferricyanide which was present only at one side of BLM. The photocurrent induced by blue light absorbed by both carotenoid and chlorophyll pigments was found to be much higher than that induced by red light absorbed exclusively by chlorophyll despite higher intensity of the red light applied, in agreement with the rate of photosynthetic oxygen evolution induced by blue and red light (Gruszecki et al., Z. Naturforsch, 50c (1995) 61-68). (C) 1997 Elsevier Science S.A.

  66. Gruszecki, W. I. Strzalka, K. Radunz, A. Schmid, G. H., Cyclic electron flow around photosystem II as examined by photosynthetic oxygen evolution induced by short light flashes, Zeitschrift Fur Naturforschung C-a Journal of Biosciences, 52(3-4), 1997, 175-179

    Abstract:
    Photosynthetic oxygen evolution from photosystem II particles was analyzed as consequence of a train of short (5 mu s) flashes of different light quality and different intensities to study cyclic electron flow around photosystem II. Damped oscillations of the amplitudes of O-2-evolution corresponding to a flash sequence were fitted numerically and analyzed in terms of a nonhomogeneous distribution of misses, represented by the probability parameter alpha(i). Application of red light, known to promote cyclic electron flow around photosystem II (Gruszecki et al., 1995) results in a considerable increase of all alpha(i), indicating that at the molecular level the misses may be interpreted as resulting from a competition for the reduction of oxidized P680 between cyclic electron flow and the electron now coming from the water splitting enzyme. In accordance with previous findings, application of light flashes of the spectrum covering the absorption region of carotenoids resulted in an inhibition of cyclic electron flow and a pronounced decrease of the level of the miss parameter. Possible molecular mechanisms for the activity control of this cyclic electron transport around photosystem II by carotenoids are discussed.

  67. Gruszecki, W. I. Matula, M. Naomi, K. C. Koyama, Y. Krupa, Z., Cis-trans-isomerization of violaxanthin in LHC II: Violaxanthin isomerization cycle within the violaxanthin cycle, Biochimica Et Biophysica Acta-Bioenergetics, 1319(2-3), 1997, 267-274

    Abstract:
    Chlorophyll fluorescence excitation and emission spectroscopy, electron absorption spectroscopy and resonance Raman spectrometry of light-harvesting pigment-protein complex of Photosystem II (LHC II), isolated and incorporated to liposomes, indicate that a carotenoid pigment violaxanthin is present in this complex in conformation 15, 15'-cis. Light- induced cis-trans-isomerization of violaxanthin is combined with an energetic uncoupling of this antenna pigment from chlorophyll and is interpreted in terms of detachment of this carotenoid from protein - the process of making violaxanthin available for de-epoxidation within the lipid phase of the thylakoid membrane. It is also demonstrated that the process of heat-induced detachment of violaxanthin from LHC II is not combined with a cis-trans-isomerization.

  68. Gruszecki, W. I. Matula, M. MysliwaKurdziel, B. Kernen, P. Krupa, Z. Strzalka, K., Effect of xanthophyll pigments on fluorescence of chlorophyll a in LHC II embedded to liposomes, Journal of Photochemistry and Photobiology B-Biology, 37(1-2), 1997, 84-90

    Abstract:
    A major light-harvesting pigment-protein complex of Photosystem II (LHC II) isolated from rye leaves was incorporated to egg yolk lecithin Liposomes containing various amounts (0-0.6 mol% with respect to lipid) of xanthophyll pigments: violaxanthin, lutein or zeaxanthin. It appeared that the addition of xanthophylls increased the level of the chlorophyll a fluorescence emission despite the screening effect of additional pigments in the system. Another phenomenon documented by the 77 K fluorescence emission spectra was the xanthophyll-related desaggregation of LHC II within the lipid phase of liposomes. The analysis of the parameters of chlorophyll a fluorescence decay in comparison to steady state fluorescence emission let us conclude that the fluorescence reabsorption in aggregated LHC II was a major cause of the lower level of fluorescence emission in that state of antenna proteins. Chlorophyll singlet excitations quenching brought about by violaxanthin, lutein and zeaxanthin is also documented in liposomes containing incorporated LHC II and exogenous xanthophyll pigments, and in liposomes containing xanthophyll pigments and chlorophyll b.

  69. Gabrielska, J. Gruszecki, W. I., Zeaxanthin (dihydroxy-beta-carotene but not beta-carotene rigidifies lipid membranes: A H-1-NMR study of carotenoid-egg phosphatidylcholine liposomes, Biochimica Et Biophysica Acta-Biomembranes, 1285(2), 1996, 167-174

    Abstract:
    H-1-NMR technique was applied to study liposomes formed with egg-yolk phosphatidylcholine containing as an additional component two carotenoid pigments: Chi-carotene or zeaxanthin (dihydrohy-beta-carotene). A strong rigidifying effect of zeaxanthin but not of beta-carotene with respect to hydrophobic core of lipid bilayer was concluded from the carotenoid- dependent broadening of the NMR lines assigned to -CH2- groups and terminal -CH3 groups of lipid alkyl chains. A similar effect of zeaxanthin with respect to polar headgroups was concluded on the basis of the effect of the pigment on the shape of NMR lines attributed to -N+(CH3)(3) groups. In contrast, beta-carotene increases motional freedom of lipid polar headgroups. The inclusion of both carotenoids to liposomes resulted in the enhanced penetration of Pr3+ ions to the polar zone of the external layer of a membrane monitored by the splitting of the -N+(CH3)(3) signal, the effect of beta- carotene being much more pronounced. Differences in the effect on membrane structure and molecular dynamics observed for beta- carotene and its polar derivative are discussed in terms of organization of a carotenoid-containing lipid membrane.

  70. Wojtowicz, K. PawlikowskaPawlega, B. Gawron, A. Misiak, L. E. Gruszecki, W. I., Modifying effect of quercetin on the lipid membrane, Folia Histochemica Et Cytobiologica, 34(), 1996, 49-50

  71. Gruszecki, W. I. Matula, M. Daniluk, A. Krupa, Z., Increased heat emission in photosynthetic apparatus of rye subjected to light stress, Journal of Photochemistry and Photobiology B-Biology, 32(1-2), 1996, 67-69

    Abstract:
    The calorimetric technique was applied to monitor thermal energy dissipation in leaves of rye (Secale cereale L.) illuminated with increasing light intensity. Illumination with light of higher intensity than that at which plants were grown before the experiment was followed by the increase of thermal energy dissipation. Such a phenomenon, considered as a photoprotection of photosynthetic apparatus against overexcitation and photodamage, was correlated with the activity of the xanthophyll cycle. Possible photophysical mechanisms linking violaxanthin de-epoxidation within the xanthophyll cycle and increased heat emission are discussed briefly.

  72. Gruszecki, W. I. Strzalka, K. Bader, K. P. Radunz, A. Schmid, G. H., Involvement of the xanthophyll cycle in regulation of cyclic electron flow around photosystem II, Zeitschrift Fur Naturforschung C-a Journal of Biosciences, 51(1-2), 1996, 47-52

    Abstract:
    In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosynthetic apparatus by light is under control of the xanthophyll cycle. The combination of different light quality and thylakoids having various levels of xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means of mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and of light-induced oxygen uptake indicate that the de-epoxidation of violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin.


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