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46 results on '"Ughy, Bettina"'

8. Long- and short-term acclimation of the photosynthetic apparatus to salinity in Chlamydomonas reinhardtii. The role of Stt7 protein kinase

Author

Devadasu, Elsinraju, primary, Kanna, Sai Divya, additional, Neelam, Satyabala, additional, Yadav, Ranay Mohan, additional, Nama, Srilatha, additional, Akhtar, Parveen, additional, Polgár, Tamás F., additional, Ughy, Bettina, additional, Garab, Győző, additional, Lambrev, Petar H., additional, and Subramanyam, Rajagopal, additional

Published
2023
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9. Lipid polymorphism of plant thylakoid membranes. Structural and functional units associated with non-bilayer phases

Author

Dlouhý, Ondřej, primary, Karlický, Václav, additional, Javornik, Uroš, additional, Kurasová, Irena, additional, Zsiros, Ottó, additional, Šket, Primož, additional, Kanna, Divya, additional, Večeřová, Kristýna, additional, Böde, Kinga, additional, Urban, Otmar, additional, Gasanoff, Edward S., additional, Plavec, Janez, additional, Špunda, Vladimír, additional, Ughy, Bettina, additional, and Garab, Győző, additional

Published
2022
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10. Structural Entities Associated with Different Lipid Phases of Plant Thylakoid Membranes—Selective Susceptibilities to Different Lipases and Proteases

Author

Dlouhý, Ondřej, primary, Karlický, Václav, additional, Javornik, Uroš, additional, Kurasová, Irena, additional, Zsiros, Ottó, additional, Šket, Primož, additional, Kanna, Sai Divya, additional, Böde, Kinga, additional, Večeřová, Kristýna, additional, Urban, Otmar, additional, Gasanoff, Edward S., additional, Plavec, Janez, additional, Špunda, Vladimír, additional, Ughy, Bettina, additional, and Garab, Győző, additional

Published
2022
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15. Salt Stress Induces Paramylon Accumulation and Fine-Tuning of the Macro-Organization of Thylakoid Membranes in Euglena gracilis Cells

Author

Kanna, Sai Divya, primary, Domonkos, Ildikó, additional, Kóbori, Tímea Ottília, additional, Dergez, Ágnes, additional, Böde, Kinga, additional, Nagyapáti, Sarolta, additional, Zsiros, Ottó, additional, Ünnep, Renáta, additional, Nagy, Gergely, additional, Garab, Gyözö, additional, Szilák, László, additional, Solymosi, Katalin, additional, Kovács, László, additional, and Ughy, Bettina, additional

Published
2021
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19. Phycobilisome rod mutants in Synechocystis sp. strain PCC6803

Author

Ughy, Bettina and Ajlani, Ghada

Subjects
Plant mutation -- Research, Protein research, Biological sciences
Abstract

The phycobilisome is a large pigment-protein assembly that harvests light energy for photosynthesis. This supramolecular complex is composed of two main structures: a core substructure and peripheral rods. Linker polypeptides assemble phycobiliproteins within these structures and optimize light absorption and energy transfer. Mutations have been constructed in three rod-linker-coding genes located in the cpc operon of Synechocystis sp. strain PCC6803. The cpcC1 gene encoding the 33 kDa linker is found to be epistatic to cpcC2 encoding the 30 kDa linker, indicating a specific role for each of these two linkers in rod growth. This corroborates studies on the sequential degradation of phycobilisomes upon nitrogen starvation. Three allelic mutants affecting cpcC2 revealed a polar effect of commonly used cassettes (aphl, aadA) on the operon steady-state transcripts and an effect of rod linker availability on the amount of phycocyanin incorporated in the phycobilisome. This led to the proposal that regulation of rod length could occur through processing of transcripts upstream of the cpcC2 gene.

Published
2004

22. Anisotropic Circular Dichroism of Light-Harvesting Complex II in Oriented Lipid Bilayers: Theory Meets Experiment

Author

Akhtar, Parveen, primary, Lindorfer, Dominik, additional, Lingvay, Mónika, additional, Pawlak, Krzysztof, additional, Zsiros, Ottó, additional, Siligardi, Giuliano, additional, Jávorfi, Tamás, additional, Dorogi, Márta, additional, Ughy, Bettina, additional, Garab, Győző, additional, Renger, Thomas, additional, and Lambrev, Petar H., additional

Published
2019
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27. Phosphatidylglycerol is implicated in divisome formation and metabolic processes of cyanobacteria

Author

Kóbori, Tímea O., primary, Uzumaki, Tatsuya, additional, Kis, Mihály, additional, Kovács, László, additional, Domonkos, Ildikó, additional, Itoh, Shigeru, additional, Krynická, Vendula, additional, Kuppusamy, Saravanan G., additional, Zakar, Tomas, additional, Dean, Jason, additional, Szilák, László, additional, Komenda, Josef, additional, Gombos, Zoltán, additional, and Ughy, Bettina, additional

Published
2018
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29. Lipid polymorphism in chloroplast thylakoid membranes - as revealed by 31P-NMR and time-resolved merocyanine fluorescence spectroscopy

Author

Garab, Gyozo, Ughy, Bettina, De Waard, Pieter, Akhtar, Parveen, Javornik, Uroš, Kotakis, Christos, Šket, Primož, Karlický, Václav, Materová, Zuzana, Špunda, Vladimír, Plavec, Janez, Van Amerongen, Herbert, Vígh, László, van As, Henk, Lambrev, Petar H., Garab, Gyozo, Ughy, Bettina, De Waard, Pieter, Akhtar, Parveen, Javornik, Uroš, Kotakis, Christos, Šket, Primož, Karlický, Václav, Materová, Zuzana, Špunda, Vladimír, Plavec, Janez, Van Amerongen, Herbert, Vígh, László, van As, Henk, and Lambrev, Petar H.

Abstract

Chloroplast thylakoid membranes contain virtually all components of the energy-converting photosynthetic machinery. Their energized state, driving ATP synthesis, is enabled by the bilayer organization of the membrane. However, their most abundant lipid species is a non-bilayer-forming lipid, monogalactosyl-diacylglycerol; the role of lipid polymorphism in these membranes is poorly understood. Earlier 31P-NMR experiments revealed the coexistence of a bilayer and a non-bilayer, isotropic lipid phase in spinach thylakoids. Packing of lipid molecules, tested by fluorescence spectroscopy of the lipophilic dye, merocyanine-540 (MC540), also displayed heterogeneity. Now, our 31P-NMR experiments on spinach thylakoids uncover the presence of a bilayer and three non-bilayer lipid phases; time-resolved fluorescence spectroscopy of MC540 also reveals the presence of multiple lipidic environments. It is also shown by 31P-NMR that: (i) some lipid phases are sensitive to the osmolarity and ionic strength of the medium, (ii) a lipid phase can be modulated by catalytic hydrogenation of fatty acids and (iii) a marked increase of one of the non-bilayer phases upon lowering the pH of the medium is observed. These data provide additional experimental evidence for the polymorphism of lipid phases in thylakoids and suggest that non-bilayer phases play an active role in the structural dynamics of thylakoid membranes.

Published
2017

31. Lipid polymorphism in chloroplast thylakoid membranes – as revealed by 31P-NMR and time-resolved merocyanine fluorescence spectroscopy

Author

Garab, Győző, primary, Ughy, Bettina, additional, Waard, Pieter de, additional, Akhtar, Parveen, additional, Javornik, Uroš, additional, Kotakis, Christos, additional, Šket, Primož, additional, Karlický, Václav, additional, Materová, Zuzana, additional, Špunda, Vladimír, additional, Plavec, Janez, additional, van Amerongen, Herbert, additional, Vígh, László, additional, As, Henk Van, additional, and Lambrev, Petar H., additional

Published
2017
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41. Role of phosphatidylglycerol in the function and assembly of Photosystem II reaction center, studied in a cdsA-inactivated PAL mutant strain of Synechocystis sp. PCC6803 that lacks phycobilisomes

Author

Laczkó-Dobos, Hajnalka, primary, Ughy, Bettina, additional, Tóth, Szilvia Z., additional, Komenda, Josef, additional, Zsiros, Ottó, additional, Domonkos, Ildikó, additional, Párducz, Árpád, additional, Bogos, Balázs, additional, Komura, Masayuki, additional, Itoh, Shigeru, additional, and Gombos, Zoltán, additional

Published
2008
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42. 2P360 Requirement of Phosphatidylglycerol for the assembly and function of photosystem I and II reaction centers(43. Photosynthesis,Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)

Author

Uzumaki, Tatsuya, primary, Komenda, Josef, additional, Komura, Masayuki, additional, Ughy, Bettina, additional, Domonkos, Ildiko, additional, Sallai, Anna, additional, Fukushima, Yoshimasa, additional, Bogos, Balazs, additional, Wada, Hajime, additional, Gombos, Zoltan, additional, and Itoh, Shigeru, additional

Published
2006
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44. Two functional sites of phosphatidylglycerol for regulation of reaction of plastoquinone QB in photosystem II

Author

Itoh, Shigeru, Kozuki, Takashi, Nishida, Koji, Fukushima, Yoshimasa, Yamakawa, Hisanori, Domonkos, Ildikó, Laczkó-Dobos, Hajnalka, Kis, Mihály, Ughy, Bettina, and Gombos, Zoltán

Subjects
*PHOSPHATIDYLGLYCEROL, *QUINONE, *ELECTRON transport, *BENZOQUINONES, *CYANOBACTERIA, *SYNECHOCYSTIS
Abstract

Abstract: Functional roles of an anionic lipid phosphatidylglycerol (PG) were studied in pgsA-gene-inactivated and cdsA-gene-inactivated/phycobilisome-less mutant cells of a cyanobacterium Synechocystis sp. PCC 6803, which can grow only in PG-supplemented media. 1) A few days of PG depletion suppressed oxygen evolution of mutant cells supported by p-benzoquinone (BQ). The suppression was recovered slowly in a week after PG re-addition. Measurements of fluorescence yield indicated the enhanced sensitivity of QB to the inactivation by BQ. It is assumed that the loss of low-affinity PG (PGL) enhances the affinity for BQ that inactivates QB. 2) Oxygen evolution without BQ, supported by the endogenous electron acceptors, was slowly suppressed due to the direct inactivation of QB during 10days of PG depletion, and was recovered rapidly within 10h upon the PG re-addition. It is concluded that the loss of high-affinity PG (PGH) displaces QB directly. 3) Electron microscopy images of PG-depleted cells showed the specific suppression of division of mutant cells, which had developed thylakoid membranes attaching phycobilisomes (PBS). 4) Although the PG-depletion for 14days decreased the chlorophyll/PBS ratio to about 1/4, florescence spectra/lifetimes were not modified indicating the flexible energy transfer from PBS to different numbers of PSII. Longer PG-depletion enhanced allophycocyanin fluorescence at 683nm with a long 1.2ns lifetime indicating the suppression of energy transfer from PBS to PSII. 5) Action sites of PGH, PGL and other PG molecules on PSII structure are discussed. [Copyright &y& Elsevier]

Published
2012
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45. Lipid polymorphism in chloroplast thylakoid membranes - as revealed by 31 P-NMR and time-resolved merocyanine fluorescence spectroscopy.

Author

Garab G, Ughy B, Waard P, Akhtar P, Javornik U, Kotakis C, Šket P, Karlický V, Materová Z, Špunda V, Plavec J, van Amerongen H, Vígh L, As HV, and Lambrev PH

Subjects
Catalysis, Hydrogen-Ion Concentration, Lipids chemistry, Magnetic Resonance Spectroscopy methods, Phosphorus Isotopes, Spectrometry, Fluorescence methods, Thylakoids chemistry, Thylakoids metabolism
Abstract

Chloroplast thylakoid membranes contain virtually all components of the energy-converting photosynthetic machinery. Their energized state, driving ATP synthesis, is enabled by the bilayer organization of the membrane. However, their most abundant lipid species is a non-bilayer-forming lipid, monogalactosyl-diacylglycerol; the role of lipid polymorphism in these membranes is poorly understood. Earlier 31 P-NMR experiments revealed the coexistence of a bilayer and a non-bilayer, isotropic lipid phase in spinach thylakoids. Packing of lipid molecules, tested by fluorescence spectroscopy of the lipophilic dye, merocyanine-540 (MC540), also displayed heterogeneity. Now, our 31 P-NMR experiments on spinach thylakoids uncover the presence of a bilayer and three non-bilayer lipid phases; time-resolved fluorescence spectroscopy of MC540 also reveals the presence of multiple lipidic environments. It is also shown by 31 P-NMR that: (i) some lipid phases are sensitive to the osmolarity and ionic strength of the medium, (ii) a lipid phase can be modulated by catalytic hydrogenation of fatty acids and (iii) a marked increase of one of the non-bilayer phases upon lowering the pH of the medium is observed. These data provide additional experimental evidence for the polymorphism of lipid phases in thylakoids and suggest that non-bilayer phases play an active role in the structural dynamics of thylakoid membranes.

Published
2017
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46. Proteins, glycerolipids and carotenoids in the functional photosystem II architecture.

Author

Sozer O, Kis M, Gombos Z, and Ughy B

Subjects
Arabidopsis physiology, Chlamydomonas physiology, Photosynthetic Reaction Center Complex Proteins metabolism, Synechococcus physiology, Thylakoids physiology, beta Carotene metabolism, Carotenoids metabolism, Galactolipids metabolism, Glycolipids metabolism, Phosphatidylglycerols metabolism, Photosynthesis physiology, Photosystem II Protein Complex metabolism
Abstract

Photosystem II (PSII), the first supercomplex of the electron transport chain, governs the energy transfer using harvested light energy, which is transformed into biochemical energy. Phosphatidylglycerol and sulfoquinovosyl diacylglycerol, the anionic lipids of photosynthetic organisms, together with a neutral lipid, digalactosyldiacylglycerol, assist in the assembly of photosynthetic complexes. These lipids and carotenoids serve as mortar for the proteins which act as bricks in the construction of the active photosynthetic machinery, and they have determinative roles in the oligomerization of protein subunits. X-ray crystallographic localization of glycerolipids and carotenoids revealed that they are present at functionally and structurally important sites of both the PSI and PSII reaction centers. Phosphatidylglycerol is involved in the formation of the reaction-center oligomers and controls electron transport at the acceptor site of PSII. Digalactosyldiacylglycerol, together with phosphatidylglycerol, is involved in the electron transport at the donor site. Phosphatidylglycerol and carotenoids are needed to glue CP43 to the reaction center core. Carotenoids are protective agents, which prevent photosynthetic complexes from degradation caused by reactive oxygen species.

Published
2011
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