Marina Kozuleva - Academia.edu (original) (raw)

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Papers by Marina Kozuleva

In this study we describe the mechanisms of reactive oxygen species (ROS) production in the photo... more In this study we describe the mechanisms of reactive oxygen species (ROS) production in the photosynthetic electron transport chain of higher plants chloroplasts under illumination. We implement an improved method for the measurement of hydrogen peroxide (H 2 O 2 ) production in lipid phase of photosynthetic membranes of chloroplasts. Total rate of H 2 O 2 production and the production within the thylakoid membrane under operation of photosynthetic electron transport chain is evaluated. Obtained data show that even in the presence of an efficient electron acceptor, methyl viologen, an increase in light intensity leads to an increase in H 2 O 2 production mainly within the thylakoid membranes. The role of H 2 O 2 produced within the photosynthetic biological membrane is discussed.

Cell Metabolism - Cell Homeostasis and Stress Response, 2012

Photosynthesis Research, 2010

The contribution to reduction of oxygen by ferredoxin (Fd) to the overall reduction of oxygen in ... more The contribution to reduction of oxygen by ferredoxin (Fd) to the overall reduction of oxygen in isolated pea thylakoids was studied in the presence of Fd versus Fd ? NADP ? . The overall rate of electron transport was measured using a determination of Photosystem II quantum yield from chlorophyll fluorescence parameters, and the rate of oxidation of Fd was measured from the light-induced redox changes of Fd. At low light intensity, increasing Fd concentration from 5 to 30 lM in the absence of NADP ? increased the proportion of oxygen reduction by Fd from 25-35 to 40-60% in different experiments. This proportion decreased with increasing light intensity. When NADP ? was added in the presence of 15 lM Fd, which was optimal for the NADP ? reduction rate, the participation of Fd in the reduction of oxygen was low, no more than 10%, and it also decreased with increasing light intensity. At high light intensity, the overall oxygen reduction rates in the presence of Fd ? NADP ? and in the presence of Fd alone were comparable. The significance of reduction of dioxygen either by watersoluble Fd or by the membrane-bound carriers of the photosynthetic electron transport chain for redox signaling under different light intensities is discussed.

FEBS Letters, 2011

Accumulation of nitroxide radicals, DCP Å or TMT Å , under illumination of a thylakoid suspension... more Accumulation of nitroxide radicals, DCP Å or TMT Å , under illumination of a thylakoid suspension containing either hydrophilic, DCP-H, or lipophilic, TMT-H, cyclic hydroxylamines that have high rate constants of the reaction with superoxide radicals, was measured using ESR. A slower accumulation of TMT Å in contrast with DCP Å accumulation was explained by re-reduction of TMT Å by the carriers of the photosynthetic electron transport chain within the membrane. Superoxide dismutase suppressed TMT Å accumulation to a lesser extent than DCP Å accumulation. The data are interpreted as evidencing the production of intramembrane superoxide in thylakoids.

Biochimica et Biophysica Acta (BBA) - Bioenergetics, 2012

Light-induced generation of superoxide radicals and hydrogen peroxide in isolated thylakoids has ... more Light-induced generation of superoxide radicals and hydrogen peroxide in isolated thylakoids has been studied with a lipophilic spin probe, cyclic hydroxylamine 1-hydroxy-4-isobutyramido-2,2,6,6-tetramethylpiperidinium (TMT-H) to detect superoxide radicals, and the spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitron (4-POBN) to detect hydrogen peroxide-derived hydroxyl radicals. Accumulation of the radical products of the above reactions has been followed using electron paramagnetic resonance. It is found that the increased production of superoxide radicals and hydrogen peroxide in higher light is due to the enhanced production of these species within the thylakoid membrane, rather than outside the membrane. Fluorescent probe Amplex red, which forms fluorescent product, resorufin, in the reaction with hydrogen peroxide, has been used to detect hydrogen peroxide outside isolated chloroplasts using confocal microscopy. Resorufin fluorescence outside the chloroplasts is found to be suppressed by 60% in the presence of the inhibitor of aquaporins, acetazolamide (AZA), indicating that hydrogen peroxide can diffuse through the chloroplast envelope aquaporins. It is demonstrated that AZA also inhibits carbonic anhydrase activity of the isolated envelope. We put forward a hypothesis that carbonic anhydrase presumably can be attached to the envelope aquaporins. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.

a b s t r a c t O 2 reduction was investigated in photosystem I (PS I) complexes isolated from cy... more a b s t r a c t O 2 reduction was investigated in photosystem I (PS I) complexes isolated from cyanobacteria Synechocystis sp. PCC 6803 wild type (WT) and menB mutant strain, which is unable to synthesize phylloquinone and contains plastoquinone at the quinone-binding site A 1 . PS I complexes from WT and menB mutant exhibited different dependencies of O 2 reduction on light intensity, namely, the values of O 2 reduction rate in WT did not reach saturation at high intensities, in contrast to the values in menB mutant. The obtained results suggest the immediate phylloquinone involvement in the lightinduced O 2 reduction by PS I.

In this study we describe the mechanisms of reactive oxygen species (ROS) production in the photo... more In this study we describe the mechanisms of reactive oxygen species (ROS) production in the photosynthetic electron transport chain of higher plants chloroplasts under illumination. We implement an improved method for the measurement of hydrogen peroxide (H 2 O 2 ) production in lipid phase of photosynthetic membranes of chloroplasts. Total rate of H 2 O 2 production and the production within the thylakoid membrane under operation of photosynthetic electron transport chain is evaluated. Obtained data show that even in the presence of an efficient electron acceptor, methyl viologen, an increase in light intensity leads to an increase in H 2 O 2 production mainly within the thylakoid membranes. The role of H 2 O 2 produced within the photosynthetic biological membrane is discussed.

Cell Metabolism - Cell Homeostasis and Stress Response, 2012

Photosynthesis Research, 2010

The contribution to reduction of oxygen by ferredoxin (Fd) to the overall reduction of oxygen in ... more The contribution to reduction of oxygen by ferredoxin (Fd) to the overall reduction of oxygen in isolated pea thylakoids was studied in the presence of Fd versus Fd ? NADP ? . The overall rate of electron transport was measured using a determination of Photosystem II quantum yield from chlorophyll fluorescence parameters, and the rate of oxidation of Fd was measured from the light-induced redox changes of Fd. At low light intensity, increasing Fd concentration from 5 to 30 lM in the absence of NADP ? increased the proportion of oxygen reduction by Fd from 25-35 to 40-60% in different experiments. This proportion decreased with increasing light intensity. When NADP ? was added in the presence of 15 lM Fd, which was optimal for the NADP ? reduction rate, the participation of Fd in the reduction of oxygen was low, no more than 10%, and it also decreased with increasing light intensity. At high light intensity, the overall oxygen reduction rates in the presence of Fd ? NADP ? and in the presence of Fd alone were comparable. The significance of reduction of dioxygen either by watersoluble Fd or by the membrane-bound carriers of the photosynthetic electron transport chain for redox signaling under different light intensities is discussed.

FEBS Letters, 2011

Accumulation of nitroxide radicals, DCP Å or TMT Å , under illumination of a thylakoid suspension... more Accumulation of nitroxide radicals, DCP Å or TMT Å , under illumination of a thylakoid suspension containing either hydrophilic, DCP-H, or lipophilic, TMT-H, cyclic hydroxylamines that have high rate constants of the reaction with superoxide radicals, was measured using ESR. A slower accumulation of TMT Å in contrast with DCP Å accumulation was explained by re-reduction of TMT Å by the carriers of the photosynthetic electron transport chain within the membrane. Superoxide dismutase suppressed TMT Å accumulation to a lesser extent than DCP Å accumulation. The data are interpreted as evidencing the production of intramembrane superoxide in thylakoids.

Biochimica et Biophysica Acta (BBA) - Bioenergetics, 2012

Light-induced generation of superoxide radicals and hydrogen peroxide in isolated thylakoids has ... more Light-induced generation of superoxide radicals and hydrogen peroxide in isolated thylakoids has been studied with a lipophilic spin probe, cyclic hydroxylamine 1-hydroxy-4-isobutyramido-2,2,6,6-tetramethylpiperidinium (TMT-H) to detect superoxide radicals, and the spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitron (4-POBN) to detect hydrogen peroxide-derived hydroxyl radicals. Accumulation of the radical products of the above reactions has been followed using electron paramagnetic resonance. It is found that the increased production of superoxide radicals and hydrogen peroxide in higher light is due to the enhanced production of these species within the thylakoid membrane, rather than outside the membrane. Fluorescent probe Amplex red, which forms fluorescent product, resorufin, in the reaction with hydrogen peroxide, has been used to detect hydrogen peroxide outside isolated chloroplasts using confocal microscopy. Resorufin fluorescence outside the chloroplasts is found to be suppressed by 60% in the presence of the inhibitor of aquaporins, acetazolamide (AZA), indicating that hydrogen peroxide can diffuse through the chloroplast envelope aquaporins. It is demonstrated that AZA also inhibits carbonic anhydrase activity of the isolated envelope. We put forward a hypothesis that carbonic anhydrase presumably can be attached to the envelope aquaporins. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.

a b s t r a c t O 2 reduction was investigated in photosystem I (PS I) complexes isolated from cy... more a b s t r a c t O 2 reduction was investigated in photosystem I (PS I) complexes isolated from cyanobacteria Synechocystis sp. PCC 6803 wild type (WT) and menB mutant strain, which is unable to synthesize phylloquinone and contains plastoquinone at the quinone-binding site A 1 . PS I complexes from WT and menB mutant exhibited different dependencies of O 2 reduction on light intensity, namely, the values of O 2 reduction rate in WT did not reach saturation at high intensities, in contrast to the values in menB mutant. The obtained results suggest the immediate phylloquinone involvement in the lightinduced O 2 reduction by PS I.