Oximes and nitric oxide signalling in Medicago truncatula root system architecture

2020 ◽  
Author(s):  
◽  
Javier Buezo Bravo ◽  
José Fernando Morán Juez ◽  
Raquel Esteban Terradillos
Keyword(s):  
Nitric Oxide ◽  
Crop Production ◽  
De Novo ◽  
Nitrogen Nutrition ◽  
Plant Root ◽  
Molecular Configuration ◽  
Model Legume ◽  
Oxidative Pathway ◽  
Cruciferous Plants

Nitric oxide (NO) is a widely recognized signalling molecule in plants. It affects almost every developmental step during the whole plant’s lifespan. Among all of its already described functions, NO is recognised to act synergistically with Indole-3-acetic acid (IAA), promoting the development of the secondary roots. Until now, only a few reductive NO synthesis pathways have been confirmed, whereas no oxidative pathway has been yet described. Experiments of our research group measured de novo synthesis of NO3- and NO2- in Pisum sativum and M. truncatula grown with NH4+ as the sole N source (unpublished data). This fact suggests the existence of an oxidative pathway for NH4+ in the Fabaceae family, which is proposed to be part of the signalling of the NH4+ toxicity and to participate in the alleviation mechanism. Due to their molecular configuration, oximes are very strong candidates for being the precursors of NO, and thus the first step into this nitrogen oxidation pathway. Among these oximes, Indole-3-acetaldoxime (IAOx) is particularly relevant since it is placed in the crossroad between IAA and indole glucosinolates. The role of IAOx in growth-signalling and root phenotype is poorly studied in cruciferous plants and mostly unknown in non-cruciferous plants. In this PhD thesis, we aim to demonstrate that IAOx is present in M. truncatula playing an important role of signalling during plant root development and also that this signalling is mediated by NO. For that purpose, we synthesized a set of pure IAOx and other indolic and non-indolic oximes and performed pharmacological approaches with the model legume M. truncatula. We analysed the root phenotype, quantified the indolic compounds in tissue (shoots and roots) and measured the Indole-3- acetaldehyde oxidase and IAOx dehydratase genes expression. Our data showed that all the oximes promoted the ‘superoot’ phenotype. All this matches with the hypothesis that IAOx exerts its signalling by liberating NO. This new knowledge is a step forward towards the discovery of an oxidative NO synthesis pathway in plants and throws light into the interplay between IAOx, IAA and nitrogen nutrition, which will be paramount for further field research in crop production.

Coronary nitric oxide production controls cardiac substrate metabolism during pregnancy in the dog

2008 ◽  
Vol 294 (6) ◽  
pp. H2516-H2523 ◽  
Author(s):  
Jeffrey G. Williams ◽  
Caroline Ojaimi ◽  
Khaled Qanud ◽  
Suhua Zhang ◽  
Xiaobin Xu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Glucose Oxidation ◽  
Atp Synthesis ◽  
Glycogen Metabolism ◽  
Cardiac Metabolism ◽  
Atp Production ◽  
Oxidative Pathway ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

The aim of this study was to examine the role of nitric oxide (NO) in the control of cardiac metabolism at 60 days of pregnancy (P60) in the dog. There was a basal increase in diastolic coronary blood flow during pregnancy and a statistically significant increase in cardiac output (55 ± 4%) and in cardiac NOx production (44 ± 4 to 59 ± 3 nmol/min, P < 0.05). Immunohistochemistry of the left ventricle showed an increase in endothelial nitric oxide synthase staining in the endothelial cells at P60. NO-dependent coronary vasodilation (Bezold-Jarisch reflex) was increased by 20% and blocked by NG-nitro-l-arginine methyl ester (l-NAME). Isotopically labeled substrates were infused to measure oleate, glucose uptake, and oxidation. Glucose oxidation was not significantly different in P60 hearts (5.4 ± 0.5 vs. 6.2 ± 0.4 μmol/min) but greatly increased in response to l-NAME injection (to 19.9 ± 0.9 μmol/min, P < 0.05). Free fatty acid (FFA) oxidation was increased in P60 (from 5.3 ± 0.6 to 10.4 ± 0.5 μmol/min, P < 0.05) and decreased in response to l-NAME (to 4.5 ± 0.5 μmol/min, P < 0.05). There was an increased oxidation of FFA for ATP production but no change in the respiratory quotient during pregnancy. Genes associated with glucose and glycogen metabolism were downregulated, whereas genes involved in FFA oxidation were elevated. The acute inhibition of NO shifts the heart away from FFA and toward glucose metabolism despite the downregulation of the carbohydrate oxidative pathway. The increase in endothelium-derived NO during pregnancy results in a tonic inhibition of glucose oxidation and reliance on FFA uptake and oxidation to support ATP synthesis in conjunction with upregulation of FFA metabolic enzymes.

scholarly journals Novel Use of Trinexapac-Ethyl to Study Weed Seed Germination

2014 ◽  
Vol 28 (4) ◽  
pp. 729-733 ◽  
Author(s):  
Héctor Roberto Huarte ◽  
Antonio Jesús Ruiz Carmona ◽  
María Luz Zapiola
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
De Novo ◽  
Weed Species ◽  
Synthesis Inhibitor ◽  
Seed Biology ◽  
Combined Solution ◽  
Artichoke Thistle ◽  
Germination Requirements

Understanding seed biology and onset of germination requirements is a key point for designing effective weed management programs. Gibberellins (GAs) are known to play a role in onset of germination of several species. Onset of germination often requires an increase in de novo GA content or an increase in sensitivity to GAs. Reduced germination of seeds incubated in solutions containing compounds that inhibit GA synthesis provide evidence that GAs are required to trigger germination. Trinexapac-ethyl (TE), a GA synthesis inhibitor, is frequently used as a plant growth regulator in crop production. However, to the best of our knowledge, TE has not been used to study the requirement of GAs in onset of germination. Germination studies were conducted using seeds of artichoke thistle and common teasel under a range of TE concentrations (0 to 500 μM TE), a combined solution of 125 μM TE + 100 μM GA3for artichoke, and 250 μM TE + 100 μM GA3for common teasel. Germination tests were conducted at 20/10 C (12-h thermoperiod) in darkness for artichoke and at constant 15 C with 12 h of light for common teasel. Germination of artichoke in 125 μM TE was reduced to 47% when compared with the check (95%), but the combined TE + GA3solution maintained germination at 84%. Germination of common teasel in 250 μM TE was reduced to 10% when compared with the check (91%), and the combined TE + GA3solution increased germination to 63%. These results demonstrate the utility of TE to study the role of GAs in onset of germination. This novel use of TE is a valuable option to study germination requirements of weed species, and therefore contributes to the design of weed management programs.

scholarly journals Investigating the role of nitric oxide in plant root colonisation by Streptomyces spp.

2019 ◽  
Vol 1 (1A) ◽  
Author(s):  
Jake Newitt ◽  
John Munnoch ◽  
Sarah Worsley ◽  
Matt Hutchings
Keyword(s):  
Nitric Oxide ◽  
Plant Root ◽  
Root Colonisation ◽  
Streptomyces Spp

scholarly journals The Critical Role of Tetrahydrobiopterin (BH4) Metabolism in Modulating Radiosensitivity: BH4/NOS Axis as an Angel or a Devil

2021 ◽  
Vol 11 ◽  
Author(s):  
Yang Feng ◽  
Yahui Feng ◽  
Liming Gu ◽  
Pengfei Liu ◽  
Jianping Cao ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Free Radicals ◽  
Ionizing Radiation ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Antiangiogenic Therapy ◽  
Critical Role ◽  
Cellular Radiosensitivity ◽  
Normal Tissues

Ionizing radiation and radioactive materials have been widely used in industry, medicine, science and military. The efficacy of radiotherapy and adverse effects of normal tissues are closed related to cellular radiosensitivity. Molecular mechanisms underlying radiosensitivity are of significance to tumor cell radiosensitization as well as normal tissue radioprotection. 5,6,7,8-Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthases (NOS) and aromatic amino acid hydroxylases, and its biosynthesis involves de novo biosynthesis and a pterin salvage pathway. In this review we overview the role of BH4 metabolism in modulating radiosensitivity. BH4 homeostasis determines the role of NOS, affecting the production of nitric oxide (NO) and oxygen free radicals. Under conditions of oxidative stress, such as UV-radiation and ionizing radiation, BH4 availability is diminished due to its oxidation, which subsequently leads to NOS uncoupling and generation of highly oxidative free radicals. On the other hand, BH4/NOS axis facilitates vascular normalization, a process by which antiangiogenic therapy corrects structural and functional flaws of tumor blood vessels, which enhances radiotherapy efficacy. Therefore, BH4/NOS axis may serve as an angel or a devil in regulating cellular radiosensitivity. Finally, we will address future perspectives, not only from the standpoint of perceived advances in treatment, but also from the potential mechanisms. These advances have demonstrated that it is possible to modulate cellular radiosensitivity through BH4 metabolism.

Nitrogen(II) Oxide (Nitric Oxide, NO): Its Origin, Fate and Physiological Significance. A Review

1997 ◽  
Vol 62 (9) ◽  
pp. 1355-1383 ◽  
Author(s):  
Petr Vetrovsky ◽  
Gustav Entlicher
Keyword(s):  
Nitric Oxide ◽  
Superoxide Anion ◽  
De Novo ◽  
Soluble Guanylate Cyclase ◽  
No Synthase ◽  
Transcriptional Level ◽  
Immune Systems ◽  
Important Target ◽  
Target Molecules

The nitrogen oxide (NO), a free radical molecule, plays a key role in the regulation of mammalian physiology and pathophysiology, e.g., in cardiovascular, nervous or immune systems. This molecule is produced from guanidino moiety of amino acid L-arginine with NG-hydroxy-L-arginine as intermediate and L-citrulline as a co-product of this reaction. This conversion is catalyzed by an ezyme called NO-synthase. The NO-synthase belongs to the cytochrome P450 superfamily and four its isoenzymes are known so far. Two (denoted NOS-I and III) are constitutive, generate lower amounts (pmol) of NO and are regulated by Ca++/calmodulin system. The others (NOS-II and IV) are inducible, produce a larger quantity of NO (nmol) and are regulated at a transcriptional level. The constitutive form is present, for example, in endothelial and neuronal cells whereas the inducible form is de novo synthesized as a consequence of certain stimuli (including cytokines) in macrophages, vascular smooth muscle cells and other cells. There are several target molecules for NO depending on cells. The most frequent target is supposed to be the soluble guanylate cyclase. However, superoxide anion is a very important target for NO, too. The reaction between these two molecules leads to the production of peroxynitrite, the fate of which depends on environmental conditions. Therefore, the importance of this reaction is still debated. This review deals with the nature of NO, the mechanisms of its production, the role of intermediate NG-hydroxy-L-arginine and summarizes the biology of superoxide anion with respect to its reaction with NO. A review with 218 references.

Renal arginine and protein synthesis are increased during early endotoxemia in mice

2002 ◽  
Vol 282 (2) ◽  
pp. F316-F323 ◽  
Author(s):  
Marcella M. Hallemeesch ◽  
Peter B. Soeters ◽  
Nicolaas E. P. Deutz
Keyword(s):  
Nitric Oxide ◽  
Protein Synthesis ◽  
Protein Metabolism ◽  
De Novo ◽  
Early Response ◽  
No Production ◽  
Arginine Metabolism ◽  
First Time ◽  
Adaptive Role

The kidney has an important function in arginine metabolism, because the kidney is the main endogenous source for de novo arginine production from circulating citrulline. In conditions such as sepsis, nitric oxide (NO) production is increased and is dependent on extracellular arginine availability. To elucidate the adaptive role of renal de novo arginine synthesis in a condition of increased NO production, we studied renal arginine metabolism in a mouse model of endotoxemia. Because arginine flux is largely dependent on protein flux, we also measured protein metabolism in mice. Female mice were injected intraperitoneally with lipopolysaccharide; control mice received 0.9% NaCl. Six hours later, renal blood flow was measured with the use of para-aminohippuric acid. Arginine and protein metabolism were studied using organ-balance, stable-isotope techniques. Systemic NO production was increased in the endotoxin-treated mice. In addition, renal protein synthesis and de novo arginine production from citrulline were increased. However, no effect on renal NO production was observed. In conclusion, increased renal de novo arginine production may serve to sustain systemic NO production. To our knowledge, it was shown for the first time that renal protein synthesis is enhanced in the early response to endotoxemia.

Leptin modulates nitric oxide production and lipid metabolism in human placenta

2006 ◽  
Vol 18 (4) ◽  
pp. 425 ◽  
Author(s):  
Verónica White ◽  
Elida González ◽  
Evangelina Capobianco ◽  
Carolina Pustovrh ◽  
Nora Martínez ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Lipid Metabolism ◽  
Human Placenta ◽  
De Novo ◽  
Primary Cultures ◽  
Lipid Synthesis ◽  
No Production ◽  
Dependent Manner ◽  
Lipid Catabolism

Leptin has significant effects on appetite, energy expenditure, lipid mobilisation and reproduction. During pregnancy, leptin is produced in the placenta, a tissue in which leptin receptors are highly expressed, suggesting autocrine/paracrine functions for this hormone. In the present study, a putative role of leptin as a regulator of nitric oxide (NO) production and lipid metabolism was evaluated in term human placenta. We demonstrated that leptin enhanced NO production in human placental explants (P < 0.01). Although leptin did not modify the placental levels of cholesteryl esters and phospholipids, leptin decreased levels of triglycerides (P < 0.01) and cholesterol (P < 0.001) in term human placenta. The effect of leptin on lipid mass seems to be independent of the modulation of de novo lipid synthesis because leptin did not modify the incorporation of 14C-acetate into any of the lipids evaluated. We investigated the effects of leptin on placental lipid catabolism and found that in both term human placental explants and primary cultures of trophoblastic cells, leptin increased glycerol release, an index of the hydrolysis of esterified lipids, in a dose-dependent manner. In conclusion, we have shown that leptin affects NO production and lipid catabolism in human placenta, providing supportive evidence for a role of leptin in placental functions that would determine the transfer of nutrients to the developing fetus.

scholarly journals Comparative Physiological Analysis Reveals the Role of NR-Derived Nitric Oxide in the Cold Tolerance of Forage Legumes

2019 ◽  
Vol 20 (6) ◽  
pp. 1368 ◽  
Author(s):  
Peipei Zhang ◽  
Shuangshuang Li ◽  
Pengcheng Zhao ◽  
Zhenfei Guo ◽  
Shaoyun Lu
Keyword(s):  
Nitric Oxide ◽  
Nitrate Reductase ◽  
Cold Acclimation ◽  
Cold Tolerance ◽  
Cold Treatment ◽  
No Production ◽  
Forage Legumes ◽  
Model Legume ◽  
Nr Activity

The role of nitric oxide (NO) signaling in the cold acclimation of forage legumes was investigated in this study. Medicago sativa subsp. falcata (L.) Arcang. (hereafter M. falcata) is a forage legume with a higher cold tolerance than Medicago truncatula, a model legume. Cold acclimation treatment resulted in increased cold tolerance in both M. falcata and M. truncatula, which was suppressed by pretreatment with tungstate, an inhibitor of nitrate reductase (NR), and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), a scavenger of NO. Likely, NITRATE REDUCTASE 1 (NIA1), but not NIA2 transcript, NR activity, and NO production were increased after cold treatment. Treatments with exogenous NO donors resulted in increased cold tolerance in both species. Superoxide dismutase (SOD), catalase (CAT), and ascorbate-peroxidase (APX) activities and Cu,Zn-SOD2, Cu,Zn-SOD3, cytosolic APX1 (cAPX1), cAPX3 and chloroplastic APX1 (cpAPX1) transcript levels were induced in both species after cold treatment, which was suppressed by tungstate and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Treatment with exogenous NO resulted in enhanced activities of SOD, CAT, and APX. Moreover, higher levels of NIA1 transcript, NR activity, NO production, and antioxidant enzyme activities and transcripts were observed in M. falcata as compared with M. truncatula after cold treatment. The results suggest that NR-derived NO production and upregulated antioxidant defense are involved in cold acclimation in both species, while the higher levels of NO production and its derived antioxidant enzymes are associated with the higher cold tolerance in M. falcata as compared with M. truncatula.

Sign in / Sign up

Export Citation Format

Share Document