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Conference publications

Abstracts

XXI conference

Role of Intracellular Signal Transmission in Long-Distance Interactions of Chloroplasts and Plasmalemma in Chara Cells

Bulychev A.A., Komarova A.V.

Department of Biophysics, Faculty of Biology, Moscow State University, Moscow

1 pp. (accepted)

Photosynthetic electron transport in the intact cell is subject to complex regulation owing to structural lability of thylakoid membranes, operation of alternative electron-transport pathways, generation of electrochemical proton gradient, and permanent exchange of ions and metabolites between the chloroplasts and the cytoplasm. Long-distance intracellular interactions, underlying reversible transitions between homogenous and uneven spatial distributions of photosynthetic activity attract particular attention. Microfluorometry of characean cells with application of saturation light pulses and microelectrode methods reveals three mechanisms of long-distance regulation involved in functional coordination of cell domains and signal transmission between remote cell parts. These are: (1) circulation of electric currents between functionally distinct cell domains, (2) propagation of the action potential along the internode, and (3) permanent cytoplasmic streaming. This review focuses on the dependence of photosynthetic activity on the membrane H+ transport and cytoplasmic pH, on ion fluxes associated with the plasma membrane excitation, and on the transmission of photoinduced signals with the cytoplasmic flow. Owing to the transfer of signals with the streaming cytoplasm, dynamic photosynthetic responses may appear in cell regions far away from the site of photostimulus application and may develop with a long lapse (up to 100 s) after the excitation light was extinguished.



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