scholarly journals Alternative Oxidase Pathway Optimizes Photosynthesis During Osmotic and Temperature Stress by Regulating Cellular ROS, Malate Valve and Antioxidative Systems

2016 ◽  
Vol 7 ◽  
Author(s):  
Challabathula Dinakar ◽  
Abhaypratap Vishwakarma ◽  
Agepati S. Raghavendra ◽  
Kollipara Padmasree
2021 ◽  
Vol 12 ◽  
Author(s):  
Avesh Chadee ◽  
Nicole A. Alber ◽  
Keshav Dahal ◽  
Greg C. Vanlerberghe

Chloroplasts use light energy and a linear electron transport (LET) pathway for the coupled generation of NADPH and ATP. It is widely accepted that the production ratio of ATP to NADPH is usually less than required to fulfill the energetic needs of the chloroplast. Left uncorrected, this would quickly result in an over-reduction of the stromal pyridine nucleotide pool (i.e., high NADPH/NADP+ ratio) and under-energization of the stromal adenine nucleotide pool (i.e., low ATP/ADP ratio). These imbalances could cause metabolic bottlenecks, as well as increased generation of damaging reactive oxygen species. Chloroplast cyclic electron transport (CET) and the chloroplast malate valve could each act to prevent stromal over-reduction, albeit in distinct ways. CET avoids the NADPH production associated with LET, while the malate valve consumes the NADPH associated with LET. CET could operate by one of two different pathways, depending upon the chloroplast ATP demand. The NADH dehydrogenase-like pathway yields a higher ATP return per electron flux than the pathway involving PROTON GRADIENT REGULATION5 (PGR5) and PGR5-LIKE PHOTOSYNTHETIC PHENOTYPE1 (PGRL1). Similarly, the malate valve could couple with one of two different mitochondrial electron transport pathways, depending upon the cytosolic ATP demand. The cytochrome pathway yields a higher ATP return per electron flux than the alternative oxidase (AOX) pathway. In both Arabidopsis thaliana and Chlamydomonas reinhardtii, PGR5/PGRL1 pathway mutants have increased amounts of AOX, suggesting complementary roles for these two lesser-ATP yielding mechanisms of preventing stromal over-reduction. These two pathways may become most relevant under environmental stress conditions that lower the ATP demands for carbon fixation and carbohydrate export.


2011 ◽  
Vol 25 (5) ◽  
pp. 1007-1017 ◽  
Author(s):  
Stephanie Y. Searle ◽  
Danielle S. Bitterman ◽  
Samuel Thomas ◽  
Kevin L. Griffin ◽  
Owen K. Atkin ◽  
...  

1996 ◽  
Vol 96 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Qisen Zhang ◽  
Marcel H. N. Hoefnagel ◽  
Joseph T. Wiskich
Keyword(s):  

2020 ◽  
Vol 53 (2) ◽  
Author(s):  
Khalil Ahmed Laghari ◽  
Abdul Jabbar Pirzada ◽  
Mahboob Ali Sial ◽  
Muhammad Athar Khan ◽  
Jamal Uddin Mangi

2020 ◽  
Vol 52 (5) ◽  
Author(s):  
De-Gong Wu ◽  
Qiu-Wen Zhan ◽  
Hai-Bing Yu ◽  
Bao-Hong Huang ◽  
Xin-Xin Cheng ◽  
...  

2018 ◽  
Author(s):  
Jungsuk Ko ◽  
Hoonchang yang ◽  
Hyungchae Jeon ◽  
Gyuyoung Nam ◽  
Youngseok Ryu ◽  
...  

Abstract The necessity of hot temperature stress is widely recognized as the initial stress methodology to maintain the stability of products from infant defects in device [1, 2]. However, hot temperature stress has a disadvantage in terms of stress uniformity because temperature variation according to stress environment such as chamber, board, and tester accelerates different stress effects per chips. In addition, this stress condition can cause serious reliability problem in the mass production environments. Therefore, the stress temperature should be lowered to minimize the temperature deviation due to the production environments. The reduction of stress temperature cause the lack of stress amount, so optimized stress voltage and time to maintain the stress condition is required. In this study, various stress voltage and time with decreasing temperature were evaluated in consideration of lifetime that unit elements such transistors and capacitors did not degrade by any stress conditions. In addition, it was confirmed that stress uniformity can be improved in the stress condition obtained by the evaluation. Furthermore, the enhanced initial failure screen ability was proven with mass evaluations.


Author(s):  
D-J Kim ◽  
I-G Kim ◽  
J-Y Noh ◽  
H-J Lee ◽  
S-H Park ◽  
...  

Abstract As DRAM technology extends into 12-inch diameter wafer processing, plasma-induced wafer charging is a serious problem in DRAM volume manufacture. There are currently no comprehensive reports on the potential impact of plasma damage on high density DRAM reliability. In this paper, the possible effects of floating potential at the source/drain junction of cell transistor during high-field charge injection are reported, and regarded as high-priority issues to further understand charging damage during the metal pad etching. The degradation of block edge dynamic retention time during high temperature stress, not consistent with typical reliability degradation model, is analyzed. Additionally, in order to meet the satisfactory reliability level in volume manufacture of high density DRAM technology, the paper provides the guidelines with respect to plasma damage. Unlike conventional model as gate antenna effect, the cell junction damage by the exposure of dummy BL pad to plasma, was revealed as root cause.


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