scholarly journals Microbial Volatile-Induced Accumulation of Exceptionally High Levels of Starch in Arabidopsis Leaves Is a Process Involving NTRC and Starch Synthase Classes III and IV

2011 ◽  
Vol 24 (10) ◽  
pp. 1165-1178 ◽  
Author(s):  
Jun Li ◽  
Ignacio Ezquer ◽  
Abdellatif Bahaji ◽  
Manuel Montero ◽  
Miroslav Ovecka ◽  
...  
Keyword(s):  
Time Course ◽  
Starch Content ◽  
Thioredoxin Reductase ◽  
Redox Status ◽  
Starch Synthase ◽  
Reduced Form ◽  
Starch Accumulation ◽  
Knockout Mutants ◽  
Microbial Volatiles ◽  
The Impact

Microbial volatiles promote the accumulation of exceptionally high levels of starch in leaves. Time-course analyses of starch accumulation in Arabidopsis leaves exposed to fungal volatiles (FV) emitted by Alternaria alternata revealed that a microbial volatile-induced starch accumulation process (MIVOISAP) is due to stimulation of starch biosynthesis during illumination. The increase of starch content in illuminated leaves of FV-treated hy1/cry1, hy1/cry2, and hy1/cry1/cry2 Arabidopsis mutants was many-fold lower than that of wild-type (WT) leaves, indicating that MIVOISAP is subjected to photoreceptor-mediated control. This phenomenon was inhibited by cordycepin and accompanied by drastic changes in the Arabidopsis transcriptome. MIVOISAP was also accompanied by enhancement of the total 3-phosphoglycerate/Pi ratio, and a two- to threefold increase of the levels of the reduced form of ADP-glucose pyrophosphorylase. Using different Arabidopsis knockout mutants, we investigated the impact in MIVOISAP of downregulation of genes directly or indirectly related to starch metabolism. These analyses revealed that the magnitude of the FV-induced starch accumulation was low in mutants impaired in starch synthase (SS) classes III and IV and plastidial NADP-thioredoxin reductase C (NTRC). Thus, the overall data showed that Arabidopsis MIVOISAP involves a photocontrolled, transcriptionally and post-translationally regulated network wherein photoreceptor-, SSIII-, SSIV-, and NTRC-mediated changes in redox status of plastidial enzymes play important roles.

scholarly journals Imaging NAD(H) Redox Alterations in Cryopreserved Alveolar Macrophages from Ozone-Exposed Mice and the Impact of Nutrient Starvation during Long Lag Times

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 767
Author(s):  
He N. Xu ◽  
Joanna Floros ◽  
Lin Z. Li ◽  
Shaili Amatya
Keyword(s):  
Oxidative Stress ◽  
Alveolar Macrophages ◽  
Redox State ◽  
Redox Status ◽  
Nutrient Starvation ◽  
Ozone Exposure ◽  
Reduced Form ◽  
Time Period ◽  
Lag Times ◽  
The Impact

Employing the optical redox imaging technique, we previously identified a significant redox shift of nicotinamide adenine dinucleotide (NAD and the reduced form NADH) in freshly isolated alveolar macrophages (AM) from ozone-exposed mice. The goal here was twofold: (a) to determine the NAD(H) redox shift in cryopreserved AM isolated from ozone-exposed mice and (b) to investigate whether there is a difference in the redox status between cryopreserved and freshly isolated AM. We found: (i) AM from ozone-exposed mice were in a more oxidized redox state compared to that from filtered air (FA)-exposed mice, consistent with the results obtained from freshly isolated mouse AM; (ii) under FA exposure, there was no significant NAD(H) redox difference between fresh AM that had been placed on ice for 2.5 h and cryopreserved AM; however, under ozone exposure, fresh AM were more oxidized than cryopreserved AM; (iii) via the use of nutrient starvation and replenishment and H2O2-induced oxidative stress of an AM cell line, we showed that this redox difference between cryopreserved and freshly isolated AM is likely the result of the double “hit”, i.e., the ozone-induced oxidative stress plus nutrient starvation that prevented freshly isolated AM from a full recovery after being on ice for a prolonged time period. The cryopreservation technique we developed eliminates/minimizes the effects of oxidative stress and nutrient starvation on cells. This method can be adopted to preserve lung macrophages from animal models or clinical patients for further investigations.

Relationship between Starch Accumulation and Activities of the Related Enzymes in the Leaf Sheath as a Temporary Sink Organ in Rice (Oryza sativa)

1997 ◽  
Vol 24 (5) ◽  
pp. 563 ◽  
Author(s):  
Yoshito Watanabe ◽  
Yasunori Nakamura ◽  
Ryuichi Ishii
Keyword(s):  
Biosynthetic Pathway ◽  
Starch Content ◽  
Soluble Starch ◽  
Leaf Sheath ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Regulation Mechanism ◽  
Rice Plants ◽  
Fructose 1,6 Bisphosphatase ◽  
The Relationship

The starch stored temporarily in the leaf sheath of rice plants is translocated to the grain, contributing to the grain yield. In this paper, the relationship between starch accumulation and the activities of enzymes involved in the starch biosynthetic pathway in the leaf sheaths of rice plants was examined to elucidate the regulation mechanism of starch accumulation in the temporary sink organ. When the starch content was compared between different leaf sheath positions on the main stem, the 14th leaf sheath counted from the bottom, which elongated just before anthesis, showed about a four-fold higher value than the 10th leaf sheath. Among the enzymes involved in carbohydrate metabolism, the activity of starch branching enzyme (BE, EC2.4.1.18) was greatly higher in the 14th leaf sheath than in the 10th leaf sheath, while that of ADPglucose pyrophosphorylase (EC2.7.7.27) was similar between the two leaf sheaths. The starch content increased rapidly in the period around anthesis in the 12th and 14th leaf sheaths, but did not in the 10th and 11th leaf sheath. In the higher leaf sheath position, the activity of BE changed with noticeably similar trend to the starch content. Soluble starch synthase (SSS, EC2.4.1.21), granule-bound starch synthase (GBSS, EC2.4.1.21) and plastidial fructose- 1,6-bisphosphatase (FBPase, EC3.1.3.11) were also significantly correlated with the starch content. These results suggest that BE is involved in regulation of starch metabolism, possibly in collaboration with other enzymes such as SSS, GBSS and plastidial FBPase in temporary sink organs like the leaf sheath.

scholarly journals Redox Systems in Botrytis cinerea: Impact on Development and Virulence

2014 ◽  
Vol 27 (8) ◽  
pp. 858-874 ◽  
Author(s):  
Anne Viefhues ◽  
Jens Heller ◽  
Nora Temme ◽  
Paul Tudzynski
Keyword(s):  
Botrytis Cinerea ◽  
Redox Homeostasis ◽  
Thioredoxin Reductase ◽  
Redox System ◽  
Redox Status ◽  
Redox Systems ◽  
Gene Encoding ◽  
Cellular Redox ◽  
Thioredoxin System ◽  
The Impact

The thioredoxin system is of great importance for maintenance of cellular redox homeostasis. Here, we show that it has a severe influence on virulence of Botrytis cinerea, demonstrating that redox processes are important for host-pathogen interactions in this necrotrophic plant pathogen. The thioredoxin system is composed of two enzymes, the thioredoxin and the thioredoxin reductase. We identified two genes encoding for thioredoxins (bctrx1, bctrx2) and one gene encoding for a thioredoxin reductase (bctrr1) in the genome of B. cinerea. Knockout mutants of bctrx1 and bctrr1 were severely impaired in virulence and more sensitive to oxidative stress. Additionally, Δbctrr1 showed enhanced H2O2 production and retarded growth. To investigate the impact of the second major cellular redox system, glutathione, we generated deletion mutants for two glutathione reductase genes. The effects were only marginal; deletion of bcglr1 resulted in reduced germination and, correspondingly, to retarded infection as well as reduced growth on minimal medium, whereas bcglr2 deletion had no distinctive phenotype. In summary, we showed that the balanced redox status maintained by the thioredoxin system is essential for development and pathogenesis of B. cinerea, whereas the second major cellular redox system, the glutathione system, seems to have only minor impact on these processes.

Starch synthesis and localization in post-germination Pinusedulis seedlings

1994 ◽  
Vol 24 (7) ◽  
pp. 1457-1463 ◽  
Author(s):  
J. Brad Murphy ◽  
Mark F. Hammer
Keyword(s):  
Seed Germination ◽  
Starch Content ◽  
Starch Synthesis ◽  
Minor Component ◽  
Dry Weight ◽  
Starch Synthase ◽  
Starch Accumulation ◽  
Low Levels ◽  
Starch Conversion ◽  
A Minor

Following pine seed germination, lipids in the megagametophyte are converted to sucrose, which is transported to the emerging seedling to support its growth. In several conifer species, an increase in the seedling starch content following germination has been reported. To further characterize this phenomenon, starch accumulation and localization, starch synthase (EC 2.4.1.21) activity (both soluble and granule-bound), and partitioning of exogenous 14C-sucrose were determined following germination of pinyon (Pinusedulis Engelm.) seeds. Starch was a minor component in dry embryos, accounting for only 3% of the dry weight. Starch levels increased 22-fold and 15-fold in the cotyledons and hypocotyl, respectively, by 8 days after germination. Starch accumulated to 65% of the dry weight in the cotyledons and 46% in the hypocotyl. The root and epicotyl accumulated relatively low levels of starch, only about 7%. Starch was localized primarily in the cortex and pith of the hypocotyl, the cortex of the cotyledons, and the root cap. Only granule-bound starch synthase showed a significant increase in activity during germination, and its changes more closely followed the pattern of starch accumulation. Exogenous 14C-sucrose was partitioned primarily into starch. After a 24-h labeling period, starch in both the cotyledons and hypocotyl accounted for 38% of total label (61% of the incorporated label) in these organs. In the roots, starch accounted for only 2.5 and 14%, respectively, of the total and incorporated label. The spatial and temporal pattern of starch accumulation closely paralleled previously reported patterns for the activity of sucrose synthase, which is apparently associated with the sucrose–starch conversion. Starch accumulation in the seedling accounts for approximately 50% of the sucrose transported from the megagametophyte following pinyon seed germination. Thus, starch appears to serve as an important transitory carbon pool for the growing seedling and may serve additional functions during seedling development.

scholarly journals NTRC and Thioredoxin f Overexpression Differentially Induces Starch Accumulation in Tobacco Leaves

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 543 ◽  
Author(s):  
María Ancín ◽  
Luis Larraya ◽  
Alicia Fernández-San Millán ◽  
Jon Veramendi ◽  
Tessa Burch-Smith ◽  
...  
Keyword(s):  
Starch Content ◽  
Starch Synthesis ◽  
Genetically Engineered ◽  
Starch Accumulation ◽  
Starch Metabolism ◽  
Reductive Activation ◽  
Amylolytic Enzyme ◽  
Tobacco Plants ◽  
Tobacco Leaves ◽  
The Impact

Thioredoxin (Trx) f and NADPH-dependent Trx reductase C (NTRC) have both been proposed as major redox regulators of starch metabolism in chloroplasts. However, little is known regarding the specific role of each protein in this complex mechanism. To shed light on this point, tobacco plants that were genetically engineered to overexpress the NTRC protein from the chloroplast genome were obtained and compared to previously generated Trx f-overexpressing transplastomic plants. Likewise, we investigated the impact of NTRC and Trx f deficiency on starch metabolism by generating Nicotiana benthamiana plants that were silenced for each gene. Our results demonstrated that NTRC overexpression induced enhanced starch accumulation in tobacco leaves, as occurred with Trx f. However, only Trx f silencing leads to a significant decrease in the leaf starch content. Quantitative analysis of enzyme activities related to starch synthesis and degradation were determined in all of the genotypes. Zymographic analyses were additionally performed to compare the amylolytic enzyme profiles of both transplastomic tobacco plants. Our findings indicated that NTRC overexpression promotes the accumulation of transitory leaf starch as a consequence of a diminished starch turnover during the dark period, which seems to be related to a significant reductive activation of ADP-glucose pyrophosphorylase and/or a deactivation of a putative debranching enzyme. On the other hand, increased starch content in Trx f-overexpressing plants was connected to an increase in the capacity of soluble starch synthases during the light period. Taken together, these results suggest that NTRC and the ferredoxin/Trx system play distinct roles in starch turnover.

Co-expression of AGPS and AGPL genes encoded for AGPase from cassava to enhance starch accumulation in transgenic tobacco

2016 ◽  
Vol 14 (2) ◽  
pp. 287-293
Author(s):  
Nguyễn Văn Đoài ◽  
Nguyễn Minh Hồng ◽  
Lê Thu Ngọc ◽  
Nguyễn Thị Thơm ◽  
Nguyễn Đình Trọng ◽  
...  
Keyword(s):  
Transgenic Tobacco ◽  
Higher Plants ◽  
Starch Content ◽  
Genetically Modified Crops ◽  
Starch Accumulation ◽  
35S Promoter ◽  
Effective Strategies ◽  
Plant Expression Vector ◽  
Transgenic Lines ◽  
Cassava Varieties

The AGPase (ADP-Glucose pyrophosphorylase) is one of the ubiquitous enzymes catalyzing the first step in starch biosynthesis. It plays an important role in regulation and adjusts the speed of the entire cycle of glycogen biosynthesis in bacteria and starch in plants. In higher plants, it is a heterotetramer and tetrameric enzyme consisting two large subunits (AGPL) and two small subunits (AGPS) and encoded by two genes. In this paper, both AGPS and AGPL genes were sucessfully isolated from cassava varieties KM140 and deposited in Genbank with accession numbers KU243124 (AGPS) and KU243122 (AGPL), these two genes were fused with P2a and inserted into plant expression vector pBI121 under the control of 35S promoter. The efficient of this construct was tested in transgenic N. tabacum. The presence and expression of AGPS and AGPL in transgenic plants were confirmed by PCR and Western hybridization. The starch content was quantified by the Anthrone method. Transgenic plant analysis indicated that that two targeted genes were expressed simultaneously in several transgenic tobacco lines under the control of CaMV 35S promoter.  The starch contents in 4 analyzed tobacco transgenic lines displays the increase 13-116%  compared to WT plants. These results indicated that the co-expression of AGPS and AGPL is one of effective strategies for enhanced starch production in plant. These results can provide a foundation for developing other genetically modified crops to increase starch accumulation capacity.

Type 2 diabetes mellitus in patients with acute ischemiс stroke is associated with a decrease in plasma glutathione levels

2020 ◽  
Vol 25 (5) ◽  
pp. 29-35
Author(s):  
M. Yu. Maksimova ◽  
A. V. Ivanov ◽  
K. A. Nikiforova ◽  
F. R. Ochtova ◽  
E. T. Suanova ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Redox Status ◽  
Reduced Form ◽  
Glutathione Level ◽  
Total Glutathione ◽  
Diabetes Mellitus Group ◽  
Reduced Forms

Ischemic stroke (IS) and type 2 diabetes mellitus are factors that affect the homeostasis of low-molecularweight aminothiols (cysteine, homocysteine, glutathione etc.). It has already been shown that IS in the acute period led to a decrease a level of reduced forms of aminothiols, but it is not clear whether type 2 diabetes mellitus has a noticeable effect there. Objective: to reveal the features of homeostasis of aminothiols in patients with type 2 diabetes mellitus in acute IS. Material and methods. The study involved 76 patients with primary middle cerebral artery IS in the first 10–24 hours after development of neurological symptoms. Group 1 included 15 patients with IS and type 2 diabetes mellitus, group 2 — 61 patients with IS and stress hyperglycemia. Their total plasma levels of cysteine, homocysteine, and glutathione, their reduced forms, and redox status were determined at admission (in the first 24 hours after IS). Results. There was a decrease in the level of total glutathione level (1.27 vs. 1.65 μM, p = 0.021), as well as its reduced form (0.03 vs. 0.04 μM, p = 0.007) in patients with IS and type 2 diabetes mellitus. Patients with type 2 diabetes mellitus who had a low redox status of homocysteine (0.65–1.2%) and glutathione (0.7–2.0%) were also characterized by a decrease in total glutathione level (p = 0.02; p = 0.03). Conclusion. Thus, type 2 diabetes mellitus is associated with a decrease in the level of total glutathione in acute IS. Probably, type 2 diabetes mellitus is characterized by a particular relationship between the metabolism of homocysteine, glutathione and glucose. Therefore, the search for homocysteine-dependent approaches to correct glutathione metabolism in type 2 diabetes mellitus may be of interest as an adjuvant therapy for IS.

Effects of Irrigation Amount on Grain Starch Content, Starch Synthase Activity, and Water Use Efficiency in Wheat

2009 ◽  
Vol 35 (2) ◽  
pp. 324-333 ◽  
Author(s):  
Peng-Fei CHU ◽  
Zhen-Wen YU ◽  
Xiao-Yan WANG ◽  
Tong-Hua WU ◽  
Xi-Zhi WANG
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Starch Content ◽  
Starch Synthase ◽  
Irrigation Amount ◽  
Grain Starch ◽  
Use Efficiency

scholarly journals Effect of Bacillus spp. and Brevibacillus sp. on the Photosynthesis and Redox Status of Solanum lycopersicum

Horticulturae ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 24
Author(s):  
Marino Costa-Santos ◽  
Nuno Mariz-Ponte ◽  
Maria Celeste Dias ◽  
Luísa Moura ◽  
Guilhermina Marques ◽  
...  
Keyword(s):  
Solanum Lycopersicum ◽  
Intercellular Co2 Concentration ◽  
Redox Status ◽  
Antioxidant Defenses ◽  
Photosynthetic Parameters ◽  
Plant Growth Promoting Bacteria ◽  
Potted Plants ◽  
Chlorophylls A And B ◽  
Bacillus Spp ◽  
The Impact

Plant-growth-promoting bacteria (PGPB) are gaining attention as a sustainable alternative to current agrochemicals. This study evaluated the impact of three Bacillus spp. (5PB1, 1PB1, FV46) and one Brevibacillus sp. (C9F) on the important crop tomato (Solanum lycopersicum) using the model cv. ‘MicroTom’. The effects of these isolates were assessed on (a) seedlings’ growth and vigor, and (b) adult potted plants. In potted plants, several photosynthetic parameters (chlorophylls (a and b), carotenoids and anthocyanins contents, transpiration rate, stomatal conductance, net CO2 photosynthetic rate, and intercellular CO2 concentration, and on chlorophyll fluorescence yields of light- and dark-adapted leaves)), as well as soluble sugars and starch contents, were quantified. Additionally, the effects on redox status were evaluated. While the growth of seedlings was, overall, not influenced by the strains, some effects were observed on adult plants. The Bacillus safensis FV46 stimulated the content of pigments, compared to C9F. Bacillus zhangzhouensis 5PB1 increased starch levels and was positively correlated with some parameters of the photophosphorylation and the gas exchange phases. Interestingly, Bacillus megaterium 1PB1 decreased superoxide (O2−) content, and B. safensis FV46 promoted non-enzymatic antioxidant defenses, increasing total phenol content levels. These results, conducted on a model cultivar, support the theory that these isolates differently act on tomato plant physiology, and that their activity depends on the age of the plant, and may differently influence photosynthesis. It would now be interesting to analyze the influence of these bacteria using commercial cultivars.

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