NADPH from the oxidative pentose phosphate pathway drives the operation of cyclic electron flow around photosystem I in high-intertidal macroalgae under severe salt stress

2015 ◽  
Vol 156 (4) ◽  
pp. 397-406 ◽  
Author(s):  
Xiaoping Lu ◽  
Li Huan ◽  
Shan Gao ◽  
Linwen He ◽  
Guangce Wang
Keyword(s):  
Salt Stress ◽  
Photosystem I ◽  
Pentose Phosphate Pathway ◽  
Electron Flow ◽  
Pentose Phosphate ◽  
Cyclic Electron Flow ◽  
Oxidative Pentose Phosphate Pathway

scholarly journals Glycogen metabolism jump-starts photosynthesis through the oxidative pentose phosphate pathway (OPPP) in cyanobacteria

2019 ◽  
Author(s):  
Shrameeta Shinde ◽  
Sonali P. Singapuri ◽  
Xiaohui Zhang ◽  
Isha Kalra ◽  
Xianhua Liu ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Carbon Fixation ◽  
Transition Period ◽  
Dark Respiration ◽  
Electron Flow ◽  
Glycogen Metabolism ◽  
Pentose Phosphate ◽  
Oxidative Pentose Phosphate Pathway ◽  
Cellular Respiration ◽  
Dark Light

AbstractCyanobacteria experience drastic changes in their carbon metabolism under daily light-dark cycles. In the light, the Calvin-Benson cycle fixes CO2and divert excess carbon into glycogen storage. At night, glycogen is degraded to support cellular respiration. Dark-light transition represents a universal environmental stress for cyanobacteria and other photosynthetic lifeforms. Recent studies in the field revealed the essential genetic background necessary for the fitness of cyanobacteria during diurnal growth. However, the metabolic engagement behind the dark-light transition is not well understood. In this study, we discovered that glycogen metabolism can jump-start photosynthesis in the cyanobacteriumSynechococcus elongatusPCC 7942 when photosynthesis reactions start upon light. Compared to the wild type, the glycogen mutant (ΔglgC) showed much lower photosystem II efficiency and slower photosystem I-mediated cyclic electron flow rate when photosynthesis starts. Proteomics analyses indicated that glycogen is degraded through the oxidative pentose phosphate pathway (OPPP) during dark-light transition. We confirmed that the OPPP is essential for the initiation of photosynthesis, and further showed that glycogen degradation through the OPPP is likely to contribute to the activation of key Calvin-Benson cycle enzymes by modulating NADPH levels during the transition period. This ingenious strategy helps jump-start photosynthesis in cyanobacteria following dark respiration, and stabilize the Calvin-Benson cycle under fluctuating environmental conditions. It has evolutionary advantages for the survival of photosynthetic organisms using the Calvin-Benson cycle for carbon fixation.

scholarly journals Targeting oxidative pentose phosphate pathway prevents recurrence in mutant Kras colorectal carcinomas

PLoS Biology ◽  
2019 ◽  
Vol 17 (8) ◽  
pp. e3000425 ◽  
Author(s):  
WenChao Gao ◽  
YuTing Xu ◽  
Tao Chen ◽  
ZunGuo Du ◽  
XiuJuan Liu ◽  
...  
Keyword(s):  
Pentose Phosphate Pathway ◽  
Pentose Phosphate ◽  
Oxidative Pentose Phosphate Pathway ◽  
Colorectal Carcinomas

Cyclic electron flow around photosystem I is enhanced at low pH

2014 ◽  
Vol 83 ◽  
pp. 194-199 ◽  
Author(s):  
Teena Tongra ◽  
Sudhakar Bharti ◽  
Anjana Jajoo
Keyword(s):  
Photosystem I ◽  
Electron Flow ◽  
Low Ph ◽  
Cyclic Electron Flow

scholarly journals PsaE Is Required for in Vivo Cyclic Electron Flow around Photosystem I in the Cyanobacterium Synechococcus sp. PCC 7002

1993 ◽  
Vol 103 (1) ◽  
pp. 171-180 ◽  
Author(s):  
L. Yu ◽  
J. Zhao ◽  
U. Muhlenhoff ◽  
D. A. Bryant ◽  
J. H. Golbeck
Keyword(s):  
Photosystem I ◽  
Electron Flow ◽  
Cyclic Electron Flow ◽  
Synechococcus Sp
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