Physiological Role of Cyclic Electron Flow in Higher Plants

2012 ◽  
Vol 30 (1) ◽  
pp. 100
Author(s):  
Wei HUANG ◽  
Shi-Bao ZHANG ◽  
Kun-Fang CAO
Keyword(s):  
Higher Plants ◽  
Electron Flow ◽  
Physiological Role ◽  
Cyclic Electron Flow

scholarly journals ATP compartmentation in plastids and cytosol ofArabidopsis thalianarevealed by fluorescent protein sensing

2018 ◽  
Vol 115 (45) ◽  
pp. E10778-E10787 ◽  
Author(s):  
Chia Pao Voon ◽  
Xiaoqian Guan ◽  
Yuzhe Sun ◽  
Abira Sahu ◽  
May Ngor Chan ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Fluorescent Protein ◽  
Higher Plants ◽  
Electron Flow ◽  
Cyclic Electron Flow ◽  
Linear Electron ◽  
Protein Sensing ◽  
Atp Production ◽  
Respiratory Inhibitors ◽  
Sensor Protein

Matching ATP:NADPH provision and consumption in the chloroplast is a prerequisite for efficient photosynthesis. In terms of ATP:NADPH ratio, the amount of ATP generated from the linear electron flow does not meet the demand of the Calvin–Benson–Bassham (CBB) cycle. Several different mechanisms to increase ATP availability have evolved, including cyclic electron flow in higher plants and the direct import of mitochondrial-derived ATP in diatoms. By imaging a fluorescent ATP sensor protein expressed in livingArabidopsis thalianaseedlings, we found that MgATP2−concentrations were lower in the stroma of mature chloroplasts than in the cytosol, and exogenous ATP was able to enter chloroplasts isolated from 4- and 5-day-old seedlings, but not chloroplasts isolated from 10- or 20-day-old photosynthetic tissues. This observation is in line with the previous finding that the expression of chloroplast nucleotide transporters (NTTs) inArabidopsismesophyll is limited to very young seedlings. Employing a combination of photosynthetic and respiratory inhibitors with compartment-specific imaging of ATP, we corroborate the dependency of stromal ATP production on mitochondrial dissipation of photosynthetic reductant. Our data suggest that, during illumination, the provision and consumption of ATP:NADPH in chloroplasts can be balanced by exporting excess reductants rather than importing ATP from the cytosol.

Biosynthetic mechanism and physiological role of heterocyclic ß-substituted alanines in higher plants

Amino Acids ◽  
1990 ◽  
pp. 1040-1051
Author(s):  
Fumio Ikegami ◽  
Fernand Lambein ◽  
Leslie Fowden ◽  
Isamu Murakoshi
Keyword(s):  
Higher Plants ◽  
Physiological Role

Physiological role of extracellular ribonucleases of higher plants

2011 ◽  
Vol 1 (1) ◽  
pp. 44-50 ◽  
Author(s):  
S. S. Sangaev ◽  
A. V. Kochetov ◽  
S. S. Ibragimova ◽  
B. A. Levenko ◽  
V. K. Shumny
Keyword(s):  
Higher Plants ◽  
Physiological Role

scholarly journals Uncoupling proteins in mitochondria of plants and some microorganisms.

2001 ◽  
Vol 48 (1) ◽  
pp. 145-155 ◽  
Author(s):  
W Jarmuszkiewicz
Keyword(s):  
Higher Plants ◽  
Uncoupling Protein ◽  
Physiological Role ◽  
Acanthamoeba Castellanii ◽  
Uncoupling Proteins ◽  
Protein Activity ◽  
Functional Connection ◽  
Mitochondrial Inner Membrane ◽  
Mitochondrial Carrier Family

Uncoupling proteins, members of the mitochondrial carrier family, are present in mitochondrial inner membrane and mediate free fatty acid-activated, purine-nucleotide-inhibited H+ re-uptake. Since 1995, it has been shown that the uncoupling protein is present in many higher plants and some microorganisms like non-photosynthetic amoeboid protozoon, Acanthamoeba castellanii and non-fermentative yeast Candida parapsilosis. In mitochondria of these organisms, uncoupling protein activity is revealed not only by stimulation of state 4 respiration by free fatty acids accompanied by decrease in membrane potential (these effects being partially released by ATP and GTP) but mainly by lowering ADP/O ratio during state 3 respiration. Plant and microorganism uncoupling proteins are able to divert very efficiently energy from oxidative phosphorylation, competing for deltamicroH+ with ATP synthase. Functional connection and physiological role of uncoupling protein and alternative oxidase, two main energy-dissipating systems in plant-type mitochondria, are discussed.

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