scholarly journals The activity of chloroplast NADH dehydrogenase-like complex influences the photosynthetic activity of the moss Physcomitrella patens

2020 ◽  
Author(s):  
Mattia Storti ◽  
Maria Paola Puggioni ◽  
Anna Segalla ◽  
Tomas Morosinotto ◽  
Alessandro Alboresi
Keyword(s):  
Electron Transport ◽  
Nadh Dehydrogenase ◽  
Molecular Mechanisms ◽  
Physcomitrella Patens ◽  
Physiological Role ◽  
Plant Evolution ◽  
Transport Systems ◽  
Photosynthetic Parameters ◽  
Transport Pathway ◽  
Strong Electron

ABSTRACTAlternative electron pathways contribute to the regulation of photosynthetic light reactions to meet metabolic demands in a dynamic environment. Understanding the molecular mechanisms of their activity is seminal to decipher their role in response to environmental cues and in plant adaptation. The chloroplast NADH dehydrogenase-like (NDH) complex mediates cyclic electron transport pathway around photosystem I (PSI) in different organisms like cyanobacteria, algae and various plant species but has a discontinuous distribution in the green lineage. In order to assess how its activity and physiological role changed during plant evolution, we isolated Physcomitrella patens lines knocked out of the gene NDHM which encodes for a subunit fundamental for the stability and activity of the whole complex. P. patens ndhm KO mosses showed high PSI acceptor side limitation upon illumination leading to PSI photoinhibition. Flavodiiron proteins (FLV) have similar and particularly important role in preventing PSI overreduction when plants are exposed to light fluctuations. The flva ndhm double KO mosses alteration in photosynthetic parameters leaded to a defect in plant growth under fluctuating light as compared to WT and single KO mutants. Results evidenced that, while FLV sustain strong electron transport after an abrupt change in light intensity, NDH contribution to electron transport is small. NDH still participate in modulating PSI activity and it is seminal to prevent PSI photoinhibition especially when FLV are inactive. In plants the functional overlap between NDH- and FLV-dependent electron transport systems sustains PSI activity and to prevent its photoinhibition.

scholarly journals The chloroplast NADH dehydrogenase-like complex influences the photosynthetic activity of the moss Physcomitrella patens

2020 ◽  
Vol 71 (18) ◽  
pp. 5538-5548
Author(s):  
Mattia Storti ◽  
Maria Paola Puggioni ◽  
Anna Segalla ◽  
Tomas Morosinotto ◽  
Alessandro Alboresi
Keyword(s):  
Electron Transport ◽  
Nadh Dehydrogenase ◽  
Photosynthetic Activity ◽  
Physcomitrella Patens ◽  
Physiological Role ◽  
Photosynthetic Performance ◽  
Plant Evolution ◽  
Cyclic Electron Transport ◽  
Double Knockout ◽  
Transport Pathway

Abstract Alternative electron pathways contribute to regulation of photosynthetic light reactions to adjust to metabolic demands in dynamic environments. The chloroplast NADH dehydrogenase-like (NDH) complex mediates the cyclic electron transport pathway around PSI in different cyanobacteria, algae, and plant species, but it is not fully conserved in all photosynthetic organisms. In order to assess how the physiological role of this complex changed during plant evolution, we isolated Physcomitrella patens lines knocked out for the NDHM gene that encodes a subunit fundamental for the activity of the complex. ndhm knockout mosses indicated high PSI acceptor side limitation upon abrupt changes in illumination. In P. patens, pseudo-cyclic electron transport mediated by flavodiiron proteins (FLVs) was also shown to prevent PSI over-reduction in plants exposed to light fluctuations. flva ndhm double knockout mosses had altered photosynthetic performance and growth defects under fluctuating light compared with the wild type and single knockout mutants. The results showed that while the contribution of NDH to electron transport is minor compared with FLV, NDH still participates in modulating photosynthetic activity, and it is critical to avoid PSI photoinhibition, especially when FLVs are inactive. The functional overlap between NDH- and FLV-dependent electron transport supports PSI activity and prevents its photoinhibition under light variations.

scholarly journals Regulation of electron transport is essential for photosystem I stability and plant growth

2019 ◽  
Author(s):  
Mattia Storti ◽  
Anna Segalla ◽  
Marco Mellon ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Nadh Dehydrogenase ◽  
Physcomitrella Patens ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Type I ◽  
Growth Reduction ◽  
Light Regimes ◽  
Photosynthetic Organisms

AbstractLife depends on the ability of photosynthetic organisms to exploit sunlight to fix carbon dioxide into biomass. Photosynthesis is modulated by pathways such as cyclic and pseudocyclic electron flow (CEF and PCEF). CEF transfers electrons from photosystem I to the plastoquinone pool according to two mechanisms, one dependent on proton gradient regulators (PGR5/PGRL1) and the other on the type I NADH dehydrogenase (NDH) complex. PCEF uses electrons from photosystem I to reduce oxygen; in several groups of photosynthetic organisms but not in angiosperms, it is sustained by flavodiiron proteins (FLVs). PGR5/PGRL1, NDH and FLVs are all active in the moss Physcomitrella patens, and mutants depleted in these proteins show phenotypes under specific light regimes. Here, we demonstrated that CEF and PCEF exhibit strong functional overlap and that when one protein component is depleted, the others can compensate for most of the missing activity. When multiple mechanisms are simultaneously inactivated, however, plants show damage to photosystem I and strong growth reduction, demonstrating that mechanisms for the modulation of photosynthetic electron transport are indispensable.

scholarly journals The Physiological Functionality of PGR5/PGRL1-Dependent Cyclic Electron Transport in Sustaining Photosynthesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Mingzhu Ma ◽  
Yifei Liu ◽  
Chunming Bai ◽  
Yunhong Yang ◽  
Zhiyu Sun ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Nadh Dehydrogenase ◽  
Extreme Weather Events ◽  
Cyclic Electron Transport ◽  
Linear Electron ◽  
Transport Pathway ◽  
Biochemical Processes ◽  
Weather Events ◽  
Electron Transport Pathway

The cyclic electron transport (CET), after the linear electron transport (LET), is another important electron transport pathway during the light reactions of photosynthesis. The proton gradient regulation 5 (PGR5)/PRG5-like photosynthetic phenotype 1 (PGRL1) and the NADH dehydrogenase-like complex pathways are linked to the CET. Recently, the regulation of CET around photosystem I (PSI) has been recognized as crucial for photosynthesis and plant growth. Here, we summarized the main biochemical processes of the PGR5/PGRL1-dependent CET pathway and its physiological significance in protecting the photosystem II and PSI, ATP/NADPH ratio maintenance, and regulating the transitions between LET and CET in order to optimize photosynthesis when encountering unfavorable conditions. A better understanding of the PGR5/PGRL1-mediated CET during photosynthesis might provide novel strategies for improving crop yield in a world facing more extreme weather events with multiple stresses affecting the plants.

scholarly journals The Physiological Roles of Vitamin E and Hypovitaminosis E in the Transition Period of High-Yielding Dairy Cows

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1088
Author(s):  
Satoshi Haga ◽  
Hiroshi Ishizaki ◽  
Sanggun Roh
Keyword(s):  
Dairy Cows ◽  
High Performance ◽  
Molecular Mechanisms ◽  
Transition Period ◽  
Disease Risk ◽  
Serum Vitamin ◽  
Physiological Role ◽  
Density Lipoprotein ◽  
Alpha Tocopherol ◽  
Transition Dairy Cows

Levels of alpha-tocopherol (α-Toc) decline gradually in blood throughout prepartum, reaching lowest levels (hypovitaminosis E) around calving. Despite numerous reports about the disease risk in hypovitaminosis E and the effect of α-Toc supplementation on the health of transition dairy cows, its risk and supplemental effects are controversial. Here, we present some novel data about the disease risk of hypovitaminosis E and the effects of α-Toc supplementation in transition dairy cows. These data strongly demonstrate that hypovitaminosis E is a risk factor for the occurrence of peripartum disease. Furthermore, a study on the effectiveness of using serum vitamin levels as biomarkers to predict disease in dairy cows was reported, and a rapid field test for measuring vitamin levels was developed. By contrast, evidence for how hypovitaminosis E occurred during the transition period was scarce until the 2010s. Pioneering studies conducted with humans and rodents have identified and characterised some α-Toc-related proteins, molecular players involved in α-Toc regulation followed by a study in ruminants from the 2010s. Based on recent literature, the six physiological factors: (1) the decline in α-Toc intake from the close-up period; (2) changes in the digestive and absorptive functions of α-Toc; (3) the decline in plasma high-density lipoprotein as an α-Toc carrier; (4) increasing oxidative stress and consumption of α-Toc; (5) decreasing hepatic α-Toc transfer to circulation; and (6) increasing mammary α-Toc transfer from blood to colostrum, may be involved in α-Toc deficiency during the transition period. However, the mechanisms and pathways are poorly understood, and further studies are needed to understand the physiological role of α-Toc-related molecules in cattle. Understanding the molecular mechanisms underlying hypovitaminosis E will contribute to the prevention of peripartum disease and high performance in dairy cows.

scholarly journals Electrical characteristics of amyloid beta peptides in vertical junctions

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Sohyeon Seo ◽  
Jinju Lee ◽  
Jungsue Choi ◽  
G. Hwan Park ◽  
Yeseul Hong ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Amyloid Beta ◽  
Field Effect Transistors ◽  
Brain Diseases ◽  
Electrical Characteristics ◽  
Transport Pathway ◽  
Sequence Dependence ◽  
Aβ Oligomers ◽  
Aβ Peptides

AbstractAssembled amyloid beta (Aβ) peptides have been considered pathological assemblies involved in human brain diseases, and the electron transfer or electron transport characteristics of Aβ are important for the formation of structured assemblies. Here, we report the electrical characteristics of surface-assembled Aβ peptides similar to those observed in Alzheimer’s patients. These characteristics correlate to their electron transfer characteristics. Electrical current–voltage plots of Aβ vertical junction devices show the Aβ sequence dependence of the current densities at both Aβ monomers (mono-Aβs) and Aβ oligomers (oli-Aβs), while Aβ sequence dependence is not clearly observed in the electrical characteristics of Aβ planar field effect transistors (FETs). In particular, surface oligomerization of Aβ peptides drastically decreases the activity of electron transfer, which presents a change in the electron transport pathway in the Aβ vertical junctions. Electron transport at oli-Aβ junctions is symmetric (tunneling/tunneling) due to the weak and voltage-independent coupling of the less redox-reactive oli-Aβ to the contacts, while that at mono-Aβ junctions is asymmetric (hopping/tunneling) due to redox levels of mono-Aβ voltage-dependently coupled with contact electrodes. Consequently, through vertical junctions, the sequence- and conformation-dependent electrical characteristics of Aβs can reveal their electron transfer activities.

scholarly journals Plant evolution driven by interactions with symbiotic and pathogenic microbes

Science ◽  
2021 ◽  
Vol 371 (6531) ◽  
pp. eaba6605 ◽  
Author(s):  
Pierre-Marc Delaux ◽  
Sebastian Schornack
Keyword(s):  
Cell Biology ◽  
Genetic Basis ◽  
Reverse Genetics ◽  
Molecular Mechanisms ◽  
Plant Evolution ◽  
Symbiotic Microorganisms ◽  
Protection Mechanisms ◽  
Evolutionary Trajectories ◽  
Microbe Interactions ◽  
Pathogenic Microbes

During 450 million years of diversification on land, plants and microbes have evolved together. This is reflected in today’s continuum of associations, ranging from parasitism to mutualism. Through phylogenetics, cell biology, and reverse genetics extending beyond flowering plants into bryophytes, scientists have started to unravel the genetic basis and evolutionary trajectories of plant-microbe associations. Protection against pathogens and support of beneficial, symbiotic, microorganisms are sustained by a blend of conserved and clade-specific plant mechanisms evolving at different speeds. We propose that symbiosis consistently emerges from the co-option of protection mechanisms and general cell biology principles. Exploring and harnessing the diversity of molecular mechanisms used in nonflowering plant-microbe interactions may extend the possibilities for engineering symbiosis-competent and pathogen-resilient crops.

Structure, Function, Involvement in Diseases and Targeting of 14-3-3 Proteins: An Update

2018 ◽  
Vol 25 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Ylenia Cau ◽  
Daniela Valensin ◽  
Mattia Mori ◽  
Sara Draghi ◽  
Maurizio Botta
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
Cellular Processes ◽  
Protein Partners ◽  
High Sequence Homology ◽  
Small Molecule Modulators

14-3-3 is a class of proteins able to interact with a multitude of targets by establishing protein-protein interactions (PPIs). They are usually found in all eukaryotes with a conserved secondary structure and high sequence homology among species. 14-3-3 proteins are involved in many physiological and pathological cellular processes either by triggering or interfering with the activity of specific protein partners. In the last years, the scientific community has collected many evidences on the role played by seven human 14-3-3 isoforms in cancer or neurodegenerative diseases. Indeed, these proteins regulate the molecular mechanisms associated to these diseases by interacting with (i) oncogenic and (ii) pro-apoptotic proteins and (iii) with proteins involved in Parkinson and Alzheimer diseases. The discovery of small molecule modulators of 14-3-3 PPIs could facilitate complete understanding of the physiological role of these proteins, and might offer valuable therapeutic approaches for these critical pathological states.

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