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  1. Article ; Online: Oscillations of chlorophyll fluorescence after plasma membrane excitation in Chara originate from nonuniform composition of signaling metabolites in the streaming cytoplasm.

    Bulychev, Alexander A / Strelets, Tatiana S

    Biochimica et biophysica acta. Bioenergetics

    2023  Volume 1865, Issue 1, Page(s) 149019

    Abstract: Excitable cells of higher plants and characean algae respond to stressful stimuli by generating action potentials (AP) whose regulatory influence on chlorophyll (Chl) fluorescence and photosynthesis extends over tens of minutes. Unlike plant leaves where ...

    Abstract Excitable cells of higher plants and characean algae respond to stressful stimuli by generating action potentials (AP) whose regulatory influence on chlorophyll (Chl) fluorescence and photosynthesis extends over tens of minutes. Unlike plant leaves where the efficiency of photosystem II reaction (YII) undergoes a separate reversible depression after an individual AP, characean algae exhibit long-lasting oscillations of YII after firing AP, provided that Chl fluorescence is measured on microscopic cell regions. Internodal cells of charophytes feature an extremely fast cytoplasmic streaming that stops immediately during the spike and recovers within ~10 min after AP. In this study a possibility was examined that multiple oscillations of YII and Chl fluorescence parameters (F', F
    MeSH term(s) Chara ; Fluorescence ; Hydrogen-Ion Concentration ; Cytoplasm/metabolism ; Cell Membrane/metabolism ; Chlorophyll/metabolism
    Chemical Substances Chlorophyll (1406-65-1)
    Language English
    Publishing date 2023-11-02
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 60-7
    ISSN 1879-2650 ; 1879-2596 ; 1879-260X ; 1872-8006 ; 1879-2642 ; 1879-2618 ; 0006-3002 ; 0005-2728 ; 0005-2736 ; 0304-4165 ; 0167-4838 ; 1388-1981 ; 0167-4889 ; 0167-4781 ; 0304-419X ; 1570-9639 ; 0925-4439 ; 1874-9399
    ISSN (online) 1879-2650 ; 1879-2596 ; 1879-260X ; 1872-8006 ; 1879-2642 ; 1879-2618
    ISSN 0006-3002 ; 0005-2728 ; 0005-2736 ; 0304-4165 ; 0167-4838 ; 1388-1981 ; 0167-4889 ; 0167-4781 ; 0304-419X ; 1570-9639 ; 0925-4439 ; 1874-9399
    DOI 10.1016/j.bbabio.2023.149019
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Transient depletion of transported metabolites in the streaming cytoplasm of Chara upon shading the long-distance transmission pathway.

    Bulychev, Alexander A

    Biochimica et biophysica acta. Bioenergetics

    2020  Volume 1861, Issue 10, Page(s) 148257

    Abstract: Export of reducing power from chloroplasts to cytoplasm serves to balance the NADPH/ATP ratio that is optimal for ... ...

    Abstract Export of reducing power from chloroplasts to cytoplasm serves to balance the NADPH/ATP ratio that is optimal for CO
    MeSH term(s) Biological Transport/radiation effects ; Chara/cytology ; Chara/metabolism ; Chara/radiation effects ; Cytoplasm/metabolism ; Darkness ; Kinetics
    Language English
    Publishing date 2020-07-01
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 60-7
    ISSN 1879-2650 ; 1879-2596 ; 1879-260X ; 1872-8006 ; 1879-2642 ; 1879-2618 ; 0006-3002 ; 0005-2728 ; 0005-2736 ; 0304-4165 ; 0167-4838 ; 1388-1981 ; 0167-4889 ; 0167-4781 ; 0304-419X ; 1570-9639 ; 0925-4439 ; 1874-9399
    ISSN (online) 1879-2650 ; 1879-2596 ; 1879-260X ; 1872-8006 ; 1879-2642 ; 1879-2618
    ISSN 0006-3002 ; 0005-2728 ; 0005-2736 ; 0304-4165 ; 0167-4838 ; 1388-1981 ; 0167-4889 ; 0167-4781 ; 0304-419X ; 1570-9639 ; 0925-4439 ; 1874-9399
    DOI 10.1016/j.bbabio.2020.148257
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Microfluidic interactions involved in chloroplast responses to plasma membrane excitation in Chara.

    Bulychev, Alexander A / Alova, Anna V

    Plant physiology and biochemistry : PPB

    2022  Volume 183, Page(s) 111–119

    Abstract: Adaptation of plants to environmental changes involves the mechanisms of long-distance signaling. In characean algae, these mechanisms comprise the propagation of action potential (AP) and the rotational cytoplasmic streaming acting in cooperation with ... ...

    Abstract Adaptation of plants to environmental changes involves the mechanisms of long-distance signaling. In characean algae, these mechanisms comprise the propagation of action potential (AP) and the rotational cytoplasmic streaming acting in cooperation with light-dependent exchange of ions and metabolites across the chloroplast envelope. Both excitability and cyclosis exert conspicuous effects on photosynthetic activity of chloroplasts but possible influence of cyclosis arrest on the coupling of AP stimulus to photosynthetic performance remained unexplored. In this study, fluidic interactions between anchored chloroplasts were allowed or restricted by illuminating the whole internode or a confined cell area (2 mm in diameter), respectively. Measurements of chlorophyll fluorescence parameters (F' and F
    MeSH term(s) Cell Membrane/metabolism ; Chara/metabolism ; Chloroplasts/metabolism ; Hydrogen-Ion Concentration ; Microfluidics
    Language English
    Publishing date 2022-05-10
    Publishing country France
    Document type Journal Article
    ZDB-ID 742978-2
    ISSN 1873-2690 ; 0981-9428
    ISSN (online) 1873-2690
    ISSN 0981-9428
    DOI 10.1016/j.plaphy.2022.05.005
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  4. Article ; Online: Cyclosis-mediated intercellular transmission of photosynthetic metabolites in Chara revealed with chlorophyll microfluorometry.

    Bulychev, Alexander A

    Protoplasma

    2019  Volume 256, Issue 3, Page(s) 815–826

    Abstract: Symplastic interconnections of plant cells via perforations in adjoining cell walls (plasmodesmata) enable long-distance transport of photoassimilates and signaling substances required for growth and development. The pathways and features of ... ...

    Abstract Symplastic interconnections of plant cells via perforations in adjoining cell walls (plasmodesmata) enable long-distance transport of photoassimilates and signaling substances required for growth and development. The pathways and features of intercellular movement of assimilates are often examined with fluorescent tracers whose molecular dimensions are similar to natural metabolites produced in photosynthesis. Chlorophyll fluorescence was recently found to be a sensitive noninvasive indicator of long-distance intracellular transport of physiologically produced photometabolites in characean internodes. The present work shows that the chlorophyll microfluorometry has a potential for studying the cell-to-cell transport of reducing substances released by local illumination of one internode and detected as the fluorescence increase in the neighbor internode. The method provides temporal resolution in the time frame of seconds and can be used to evaluate permeability of plasmodesmata to natural components released by illuminated chloroplasts. The results show that approximately one third of the amount of photometabolites released into the streaming cytoplasm during a 30-s pulse of local light permeates across the nodal complex with the characteristic time of ~ 10 s. The intercellular transport was highly sensitive to moderate elevations of osmolarity in the bath solution (150 mM sorbitol), which contrasts to the view that only transnodal gradients in osmolarity (and internal hydrostatic pressure) have an appreciable influence on plasmodesmal conductance. The inhibition of cell-to-cell transport was reversible and specific; the sorbitol addition had no influence on photosynthetic electron transport and the velocity of cytoplasmic streaming. The conductance of transcellular pores increased in the presence of the actin inhibitor cytochalasin D but the cell-to-cell transport was eventually suppressed due to the deceleration and cessation of cytoplasmic streaming. The results show that the permeability of plasmodesmata to low-molecular photometabolites is subject to upregulation and downregulation.
    MeSH term(s) Cations, Divalent/pharmacology ; Chara/drug effects ; Chara/physiology ; Chlorophyll/metabolism ; Cytochalasin D/pharmacology ; Cytophotometry/methods ; Cytoplasmic Streaming/drug effects ; Dehydration ; Fluorescence ; Hydrogen-Ion Concentration ; Ionophores/pharmacology ; Metabolome/drug effects ; Osmosis/drug effects ; Photosynthesis/drug effects ; Protons
    Chemical Substances Cations, Divalent ; Ionophores ; Protons ; Chlorophyll (1406-65-1) ; Cytochalasin D (22144-77-0)
    Language English
    Publishing date 2019-01-04
    Publishing country Austria
    Document type Journal Article
    ZDB-ID 123809-7
    ISSN 1615-6102 ; 0033-183X
    ISSN (online) 1615-6102
    ISSN 0033-183X
    DOI 10.1007/s00709-018-01344-0
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  5. Article ; Online: Electrical Signals at the Plasma Membrane and Their Influence on Chlorophyll Fluorescence of Chara Chloroplasts in vivo.

    Bulychev, Alexander A / Shapiguzov, Stepan Yu / Alova, Anna V

    Biochemistry. Biokhimiia

    2023  Volume 88, Issue 10, Page(s) 1455–1466

    Abstract: Action potentials of plant cells are engaged in the regulation of many cell processes, including photosynthesis and cytoplasmic streaming. Excitable cells of characean algae submerged in a medium with an elevated K+ content are capable of generating ... ...

    Abstract Action potentials of plant cells are engaged in the regulation of many cell processes, including photosynthesis and cytoplasmic streaming. Excitable cells of characean algae submerged in a medium with an elevated K+ content are capable of generating hyperpolarizing electrical responses. These active responses of plasma membrane originate upon the passage of inward electric current comparable in strength to natural currents circulating in illuminated Chara internodes. So far, it remained unknown whether the hyperpolarizing electrical signals in Chara affect the photosynthetic activity. Here, we showed that the negative shift of cell membrane potential, which drives K+ influx into the cytoplasm, is accompanied by a delayed decrease in the actual yield of chlorophyll fluorescence F' and the maximal fluorescence yield F
    MeSH term(s) Chara/metabolism ; Fluorescence ; Hydrogen-Ion Concentration ; Chloroplasts/metabolism ; Photosynthesis ; Cell Membrane/metabolism ; Chlorophyll/metabolism
    Chemical Substances Chlorophyll (1406-65-1)
    Language English
    Publishing date 2023-12-16
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1109-5
    ISSN 1608-3040 ; 0006-2979 ; 0320-9717
    ISSN (online) 1608-3040
    ISSN 0006-2979 ; 0320-9717
    DOI 10.1134/S0006297923100048
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  6. Article ; Online: Plasma membrane-chloroplast interactions activated by the hyperpolarizing response in characean cells.

    Bulychev, Alexander A / Krupenina, Natalia A / Shapiguzov, Stepan Yu / Alova, Anna V

    Plant physiology and biochemistry : PPB

    2023  Volume 201, Page(s) 107836

    Abstract: Signaling pathways in plant cells often comprise electrical phenomena developing at the plasma membrane. The action potentials in excitable plants like characean algae have a marked influence on photosynthetic electron transport and ... ...

    Abstract Signaling pathways in plant cells often comprise electrical phenomena developing at the plasma membrane. The action potentials in excitable plants like characean algae have a marked influence on photosynthetic electron transport and CO
    Language English
    Publishing date 2023-06-13
    Publishing country France
    Document type Journal Article
    ZDB-ID 742978-2
    ISSN 1873-2690 ; 0981-9428
    ISSN (online) 1873-2690
    ISSN 0981-9428
    DOI 10.1016/j.plaphy.2023.107836
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  7. Article: Microfluidic interactions involved in chloroplast responses to plasma membrane excitation in Chara

    Bulychev, Alexander A. / Alova, Anna V.

    Plant physiology and biochemistry. 2022 July 15, v. 183

    2022  

    Abstract: Adaptation of plants to environmental changes involves the mechanisms of long-distance signaling. In characean algae, these mechanisms comprise the propagation of action potential (AP) and the rotational cytoplasmic streaming acting in cooperation with ... ...

    Abstract Adaptation of plants to environmental changes involves the mechanisms of long-distance signaling. In characean algae, these mechanisms comprise the propagation of action potential (AP) and the rotational cytoplasmic streaming acting in cooperation with light-dependent exchange of ions and metabolites across the chloroplast envelope. Both excitability and cyclosis exert conspicuous effects on photosynthetic activity of chloroplasts but possible influence of cyclosis arrest on the coupling of AP stimulus to photosynthetic performance remained unexplored. In this study, fluidic interactions between anchored chloroplasts were allowed or restricted by illuminating the whole internode or a confined cell area (2 mm in diameter), respectively. Measurements of chlorophyll fluorescence parameters (F′ and Fₘ’) in cell regions located close to calcium crystal depositions revealed that the AP generation induced long-lasting Fₘ’ oscillations that persisted in illuminated cells. The AP generation often induced the F′ oscillations, whose number diminished upon the transfer of internodal cells from total to local background light. The results indicate that the AP-induced changes in photosynthetic parameters, F’ in particular, have a complex origin and comprise the internal processes caused by the elevation of stromal Ca²⁺ concentration in the analyzed chloroplasts and the stages related to ion and metabolite exchange mediated by cytoplasmic streaming. It is supposed that the composition of flowing cytoplasm is heterogeneous due to the spatial alteration of calcified and noncalcified cell sites, but this heterogeneity is enhanced and can be visualized after the transient cessation and restoration of cytoplasmic streaming.
    Keywords Chara ; action potentials ; calcium ; chlorophyll ; chloroplasts ; cytoplasmic streaming ; metabolites ; photosynthesis ; plant physiology ; plasma membrane
    Language English
    Dates of publication 2022-0715
    Size p. 111-119.
    Publishing place Elsevier Masson SAS
    Document type Article
    ZDB-ID 742978-2
    ISSN 1873-2690 ; 0981-9428
    ISSN (online) 1873-2690
    ISSN 0981-9428
    DOI 10.1016/j.plaphy.2022.05.005
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  8. Article: Cyclosis-mediated intercellular transmission of photosynthetic metabolites in Chara revealed with chlorophyll microfluorometry

    Bulychev, Alexander A

    Protoplasma. 2019 May, v. 256, no. 3

    2019  

    Abstract: Symplastic interconnections of plant cells via perforations in adjoining cell walls (plasmodesmata) enable long-distance transport of photoassimilates and signaling substances required for growth and development. The pathways and features of ... ...

    Abstract Symplastic interconnections of plant cells via perforations in adjoining cell walls (plasmodesmata) enable long-distance transport of photoassimilates and signaling substances required for growth and development. The pathways and features of intercellular movement of assimilates are often examined with fluorescent tracers whose molecular dimensions are similar to natural metabolites produced in photosynthesis. Chlorophyll fluorescence was recently found to be a sensitive noninvasive indicator of long-distance intracellular transport of physiologically produced photometabolites in characean internodes. The present work shows that the chlorophyll microfluorometry has a potential for studying the cell-to-cell transport of reducing substances released by local illumination of one internode and detected as the fluorescence increase in the neighbor internode. The method provides temporal resolution in the time frame of seconds and can be used to evaluate permeability of plasmodesmata to natural components released by illuminated chloroplasts. The results show that approximately one third of the amount of photometabolites released into the streaming cytoplasm during a 30-s pulse of local light permeates across the nodal complex with the characteristic time of ~ 10 s. The intercellular transport was highly sensitive to moderate elevations of osmolarity in the bath solution (150 mM sorbitol), which contrasts to the view that only transnodal gradients in osmolarity (and internal hydrostatic pressure) have an appreciable influence on plasmodesmal conductance. The inhibition of cell-to-cell transport was reversible and specific; the sorbitol addition had no influence on photosynthetic electron transport and the velocity of cytoplasmic streaming. The conductance of transcellular pores increased in the presence of the actin inhibitor cytochalasin D but the cell-to-cell transport was eventually suppressed due to the deceleration and cessation of cytoplasmic streaming. The results show that the permeability of plasmodesmata to low-molecular photometabolites is subject to upregulation and downregulation.
    Keywords Chara ; actin ; cell walls ; chlorophyll ; chloroplasts ; cytochalasin D ; cytoplasmic streaming ; fluorescence ; growth and development ; hydrostatic pressure ; internodes ; lighting ; metabolites ; osmolarity ; permeability ; permeates ; photosynthetic electron transport ; plasmodesmata ; sorbitol ; tracer techniques
    Language English
    Dates of publication 2019-05
    Size p. 815-826.
    Publishing place Springer Vienna
    Document type Article
    ZDB-ID 123809-7
    ISSN 1615-6102 ; 0033-183X
    ISSN (online) 1615-6102
    ISSN 0033-183X
    DOI 10.1007/s00709-018-01344-0
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  9. Article ; Online: Effects of cell excitation on photosynthetic electron flow and intercellular transport in Chara

    Bulychev, Alexander A. / Eremin, Alexey / von Rüling, Florian / Alova, Anna V.

    Protoplasma. 2023 Jan., v. 260, no. 1 p.131-143

    2023  

    Abstract: Impact of membrane excitability on fluidic transport of photometabolites and their cell-to-cell passage via plasmodesmata was examined by pulse-modulated chlorophyll (Chl) microfluorometry in Chara australis internodes exposed to dim background light. ... ...

    Abstract Impact of membrane excitability on fluidic transport of photometabolites and their cell-to-cell passage via plasmodesmata was examined by pulse-modulated chlorophyll (Chl) microfluorometry in Chara australis internodes exposed to dim background light. The cells were subjected to a series of local light (LL) pulses with a 3-min period and a 30-s pulse width, which induced Chl fluorescence transients propagating in the direction of cytoplasmic streaming along the photostimulated and the neighboring internodes. By comparing Chl fluorescence changes induced in the LL-irradiated and the adjoining internodes, the permeability of the nodal complex for the photometabolites was assessed in the resting state and after the action potential (AP) generation. The electrically induced AP had no influence on Chl fluorescence in noncalcified cell regions but disturbed temporarily the metabolite transport along the internode and caused a disproportionally strong inhibition of intercellular metabolite transmission. In chloroplasts located close to calcified zones, Chl fluorescence increased transiently after cell excitation, which indicated the deceleration of photosynthetic electron flow on the acceptor side of photosystem I. Functional distinctions of chloroplasts located in noncalcified and calcified cell areas were also manifested in different modes of LL-induced changes of Chl fluorescence, which were accompanied by dissimilar changes in efficiency of PSII-driven electron flow. We conclude that chloroplasts located near the encrusted areas and in the incrustation-free cell regions are functionally distinct even in the absence of large-scale variations of cell surface pH. The inhibition of transnodal transport after AP generation is probably due to Ca²⁺-regulated changes in plasmodesmal aperture.
    Keywords Chara ; action potentials ; chlorophyll ; chloroplasts ; fluorescence ; metabolites ; pH ; permeability ; photosystem I ; plasmodesmata
    Language English
    Dates of publication 2023-01
    Size p. 131-143.
    Publishing place Springer Vienna
    Document type Article ; Online
    ZDB-ID 123809-7
    ISSN 1615-6102 ; 0033-183X
    ISSN (online) 1615-6102
    ISSN 0033-183X
    DOI 10.1007/s00709-022-01747-0
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  10. Article ; Online: Plasma membrane–chloroplast interactions activated by the hyperpolarizing response in characean cells

    Bulychev, Alexander A. / Krupenina, Natalia A. / Shapiguzov, Stepan Yu / Alova, Anna V.

    Plant Physiology and Biochemistry. 2023 Aug., v. 201 p.107836-

    2023  

    Abstract: Signaling pathways in plant cells often comprise electrical phenomena developing at the plasma membrane. The action potentials in excitable plants like characean algae have a marked influence on photosynthetic electron transport and CO₂ assimilation. The ...

    Abstract Signaling pathways in plant cells often comprise electrical phenomena developing at the plasma membrane. The action potentials in excitable plants like characean algae have a marked influence on photosynthetic electron transport and CO₂ assimilation. The internodal cells of Characeae can also generate active electrical signals of a different type. The so called hyperpolarizing response develops under the passage of electric current whose strength is comparable to physiological currents circulating between nonuniform cell regions. The plasma membrane hyperpolarization is involved in multiple physiological events in aquatic and terrestrial plants. The hyperpolarizing response may represent an unexplored tool for studying the plasma membrane–chloroplast interactions in vivo. This study shows that the hyperpolarizing response of Chara australis internodes whose plasmalemma was preliminary converted into the K⁺-conductive state induces transient changes in maximal (Fₘ′) and actual (F′) fluorescence yields of chloroplasts in vivo. These fluorescence transients were light dependent, suggesting their relation to photosynthetic electron and H⁺ transport. The cell hyperpolarization promoted H⁺ influx that was inactivated after a single electric stimulus. The results indicate that the plasma membrane hyperpolarization drives transmembrane ion fluxes and modifies the ionic composition of cytoplasm, which indirectly (via envelope transporters) affects the pH of chloroplast stroma and chlorophyll fluorescence. Remarkably, the functioning of envelope ion transporters can be revealed in short-term experiments in vivo, without growing plants on solutions with various mineral compositions.
    Keywords Chara ; carbon dioxide ; chlorophyll ; chloroplasts ; electric current ; fluorescence ; pH ; photosynthetic electron transport ; plant physiology ; plasma membrane ; Chara internodal cells ; Electrical Signaling ; Hyperpolarizing response ; K+-conductive state ; Chlorophyll fluorescence transients ; Plasma membrane H+/OH− transport ; Plasma membrane–chloroplast interactions
    Language English
    Dates of publication 2023-08
    Publishing place Elsevier Masson SAS
    Document type Article ; Online
    ZDB-ID 742978-2
    ISSN 1873-2690 ; 0981-9428
    ISSN (online) 1873-2690
    ISSN 0981-9428
    DOI 10.1016/j.plaphy.2023.107836
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