Production and consumption of nitric oxide by denitrifyingFlexibacter canadensis

1995 ◽  
Vol 41 (7) ◽  
pp. 585-591 ◽  
Author(s):  
Qitu Wu ◽  
Roger Knowles ◽  
Yiu-Kwok Chan
Keyword(s):  
Nitric Oxide ◽  
Nitrite Reductase ◽  
Chelating Agent ◽  
No Production ◽  
Production And Consumption ◽  
Carbonyl Cyanide ◽  
No Consumption ◽  
High Concentrations ◽  
Ph Range ◽  
Triton X

Production and consumption of nitric oxide (NO) by Flexibacter canadensis cells under anaerobic conditions was investigated using a chemiluminescence NO analyzer. Net NO production from nitrite in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) was pH dependent, increased in the pH range from 4.5 to 6.5, and sharply decreased at pH >6.5. CCCP inhibited NO consumption but only at pH values ≤6.5. This can explain why CCCP stimulation of NO production depends on the pH. Denitrification of nitrite at high concentrations (≥5 mM) also resulted in net NO accumulation. Diethyldithiocarbamate, a copper chelating agent, prevented not only net production of NO during the reduction of nitrite in the presence of CCCP, but also production of nitrous oxide (N2O) from nitrite in the presence of C2H2. This suggests that F. canadensis may possess a copper-type nitrite reductase. However, cytochrome cd1- and copper-containing nitrite reductase DNA probes from Pseudomonas species did not hybridize with the total DNA of F. canadensis, indicating that the nitrite reductase of F. canadensis may possess unique properties. In addition to diethyldithiocarbamate, sulfide, carbon monoxide, azide, cyanide, hydroxylamine and Triton X-100 prevented net NO production from nitrite in the presence of CCCP, and also inhibited NO consumption. C2H2, an inhibitor of N2O reductase, did not affect NO production or consumption.Key words: nitrite reductase, nitric oxide (NO), carbonyl cyanide m-chlorophenylhydrazone (CCCP), Flexibacter canadensis.

scholarly journals The role of interleukin 12 and nitric oxide in the development of spontaneous autoimmune disease in MRL/MP-lpr/lpr mice.

1996 ◽  
Vol 183 (4) ◽  
pp. 1447-1459 ◽  
Author(s):  
F P Huang ◽  
G J Feng ◽  
G Lindop ◽  
D I Stott ◽  
F Y Liew
Keyword(s):  
Nitric Oxide ◽  
Autoimmune Disease ◽  
Cultured Cells ◽  
Daily Injection ◽  
Interleukin 12 ◽  
No Production ◽  
Necrosis Factor Alpha ◽  
Ifn Gamma ◽  
Peritoneal Cells ◽  
High Concentrations

MRL/MP-lpr/lpr (MRL/lpr) mice develop a spontaneous autoimmune disease. Serum from these mice contained significantly higher concentrations of nitrite/nitrate than serum from age-matched control MRL/MP-+/+ (MRL/+), BALB/c or CBA/6J mice. Spleen and peritoneal cells from MRL/lpr mice also produced significantly more nitric oxide (NO) than those from the control mice when cultured with interferon (IFN) gamma and lipopolysaccharide (LPS) in vitro. It is interesting to note that peritoneal cells from MRL/lpr mice also produced markedly higher concentrations of interleukin (IL) 12 than those from MRL/+ or BALB/c mice when cultured with same stimuli. It is striking that cells from MRL/lpr mice produced high concentrations of NO when cultured cells from MRL/+ or BALB/c mice. The enhanced NO synthesis induced by IFN-gamma/LPS was substantially inhibited by anti-IL-12 antibody. In addition, IL-12-induced NO production can also be markedly inhibited by anti-IFN-gamma antibody, but only weakly inhibited by anti-tumor necrosis factor alpha antibody. The effect of IL-12 on NO production was dependent on the presence of natural killer and possibly T cells. Serum from MRL/lpr mice contained significantly higher concentrations of IL-12 compared with those of MRL/+ or BALB/c control mice. Daily injection of recombinant IL-12 led to increased serum levels of IFN-gamma and NO metabolites, and accelerated glomerulonephritis in the young MRL/lpr mice (but not in the MRL/+ mice) compared with controls injected with phosphate-buffered saline alone. These data, together with previous finding that NO synthase inhibitors can ameliorate autoimmune disease in MRL/lpr mice, suggest that high capacity of such mice to produce IL-12 and their greater responsiveness to IL-12, leading to the production of high concentrations of NO, are important factors in this spontaneous model of autoimmune disease.

Effect of ionophores on denitrification inFlexibacter canadensis

1995 ◽  
Vol 41 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Qitu Wu ◽  
Roger Knowles ◽  
Donald F. Niven
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Proton Motive Force ◽  
Nitrate Transport ◽  
Nitric Oxide Reductase ◽  
Anaerobic Conditions ◽  
Intact Cells ◽  
Nitrite Production ◽  
Carbonyl Cyanide ◽  
No Consumption

Denitrification by Flexibacter canadensis was investigated by measuring the production and (or) consumption of nitrite, nitric oxide (NO), and nitrous oxide (N2O) under anaerobic conditions. Carbonyl cyanide m-chlorophenylhydrazone (CCCP), carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), 2,4-dinitrophenol, and nigericin, but not valinomycin-K+inhibited the production of nitrite and N2O from nitrate by intact cells. However, CCCP, FCCP, 2,4-dinitrophenol, nigericin, and valinomycin-K+did not affect nitrite production from nitrate by cell-free extracts. These results suggest that nitrate transport was dependent on the transmembrane pH gradient but not on the membrane potential. CCCP, FCCP, and nigericin but not 2,4-dinitrophenol and valinomycin-K+caused NO accumulation during the reduction of nitrite, and also inhibited NO consumption and N2O production from nitrite by intact cells. These results preclude an explanation for NO accumulation based on the collapse of the proton motive force by ionophores, and imply that CCCP, FCCP, and nigericin perhaps dissociated a nitrite reductase–nitric oxide reductase complex, and (or) inhibited nitric oxide reductase specifically. 2,4-Dinitrophenol and CCCP did not inhibit the reduction of N2O to dinitrogen. Addition of ≤ 1.16 μM dissolved NO did not affect the production of nitrite from nitrate, or the disappearance of nitrite or N2O. The rate of NO consumption was linear with concentrations of dissolved NO up to 67 nM. Above 67 nM NO, NO consumption was inhibited, suggesting that NO is toxic to nitric oxide reductase.Key words: ionophores, denitrification, nitric oxide, Flexibacter canadensis.

scholarly journals Identification, Functional Studies, and Genomic Comparisons of New Members of the NnrR Regulon in Rhodobacter sphaeroides

2009 ◽  
Vol 192 (4) ◽  
pp. 903-911 ◽  
Author(s):  
Angela Hartsock ◽  
James P. Shapleigh
Keyword(s):  
Nitric Oxide ◽  
Rhodobacter Sphaeroides ◽  
Nitrite Reductase ◽  
Reductase Activity ◽  
Nitrite Reduction ◽  
No Production ◽  
Nitric Oxide Reductase ◽  
New Members ◽  
Functional Studies ◽  
The Status

ABSTRACT Analysis of the Rhodobacter sphaeroides 2.4.3 genome revealed four previously unidentified sequences similar to the binding site of the transcriptional regulator NnrR. Expression studies demonstrated that three of these sequences are within the promoters of genes, designated paz, norEF, and cdgA, in the NnrR regulon, while the status of the fourth sequence, within the tat operon promoter, remains uncertain. nnrV, under control of a previously identified NnrR site, was also identified. paz encodes a pseudoazurin that is a donor of electrons to nitrite reductase. paz inactivation did not decrease nitrite reductase activity, but loss of pseudoazurin and cytochrome c2 together reduced nitrite reduction. Inactivation of norEF reduced nitrite and nitric oxide reductase activity and increased the sensitivity to nitrite in a taxis assay. This suggests that loss of norEF increases NO production as a result of decreased nitric oxide reductase activity. 2.4.3 is the only strain of R. sphaeroides with norEF, even though all four of the strains whose genomes have been sequenced have the norCBQD operon and nnrR. norEF was shown to provide resistance to nitrite when it was mobilized into R. sphaeroides strain 2.4.1 containing nirK. Inactivation of the other identified genes did not reveal any detectable denitrification-related phenotype. The distribution of members of the NnrR regulon in R. sphaeroides revealed patterns of coselection of structural genes with the ancillary genes identified here. The strong coselection of these genes indicates their functional importance under real-world conditions, even though inactivation of the majority of them does not impact denitrification under laboratory conditions.

scholarly journals The fundamental role of increased production of nitric oxide in lipopolysaccharide-induced embryonic resorption in mice

Reproduction ◽  
2003 ◽  
pp. 95-110 ◽  
Author(s):  
DG Ogando ◽  
D Paz ◽  
M Cella ◽  
AM Franchi
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
No Production ◽  
Uterine Arteries ◽  
Decidual Cells ◽  
Embryonic Resorption ◽  
High Concentrations ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Nitric oxide (NO) fulfils important functions during pregnancy and has a role in implantation, decidualization, vasodilatation and myometrial relaxation. However, at high concentrations, such as those that are produced in sepsis, NO has toxic effects as it is a free radical. The aim of this study was to characterize uterine and decidual NO production in lipopolysaccharide (LPS)-induced embryonic resorption in mice and to determine which isoforms of nitric oxide synthase (NOS) take part. LPS produced 100% embryonic resorption at 24 h, with complete fetus expulsions at 48 h. Decidual and uterine NO production were increased by LPS, with maximum production at 6 h. This increase was due to the induction of expression of inducible nitric oxide synthase (iNOS) isoform in the decidua and uterus, and neuronal nitric oxide synthase (nNOS) isoform in the decidua, as detected by western blot analysis and immunohistochemistry. LPS increased iNOS expression in decidual and myometrial cells and increased nNOS expression in decidual cells. In addition, LPS caused fibrinolysis and infiltration of mesometrial decidua by macrophages positive for iNOS and CD14 (LPS receptor). Endothelial nitric oxide synthase (eNOS) was found in decidual and uterine arteries but LPS did not modify its expression. LPS induced CD14 expression in endometrial glands, and this could have amplified the inflammatory response. Aminoguanidine, an inhibitor of iNOS activity, totally reversed the LPS-induced embryonic resorption. This result could be explained by an inhibition of the increase in NO production but also by an inhibition of the cellular infiltration and fibrinolysis. These results show that NO fulfils a fundamental role in LPS-induced embryonic resorption.

scholarly journals Chronic exposure to high fatty acids impedes receptor agonist-induced nitric oxide production and increments of cytosolic Ca2+ levels in endothelial cells

2011 ◽  
Vol 47 (3) ◽  
pp. 315-326 ◽  
Author(s):  
Yanxia Tang ◽  
GuoDong Li
Keyword(s):  
Nitric Oxide ◽  
Fatty Acids ◽  
Endothelial Cells ◽  
Chronic Exposure ◽  
Receptor Agonist ◽  
No Production ◽  
Dependent Manner ◽  
Receptor Affinity ◽  
Receptor Agonists ◽  
High Concentrations

Dyslipidemia is a common metabolic disorder in diabetes. Nitric oxide (NO) production from endothelium plays the primary role in endothelium-mediated vascular relaxation and other endothelial functions. Therefore, we investigated the effects of elevated free fatty acids (FFA) on the stimulation of NO production by phospholipase C (PLC)-activating receptor agonists (potent physiological endothelium-dependent vasodilators) and defined the possible alterations of signaling pathways implicated in this scenario. Exposure of bovine aortic endothelial cells (BAECs) to high concentrations of a mixture of fatty acids (oleate and palmitate) for 5 or 10 days significantly reduced NO production evoked by receptor agonists (bradykinin or ATP) in a time- and dose-dependent manner. Such defects were not associated with alterations of either endothelial NO synthase mass or inositol phospholipid contents but were probably due to reduced elevations of intracellular free Ca2+levels ([Ca2+]i) under these conditions. Exposure of BAECs to FFA significantly attenuated agonist-induced [Ca2+]iincreases by up to 54% in a dose- and time-dependent manner. Moreover, bradykinin receptor affinity on the cell surface was significantly decreased by high concentrations of FFA. The morphology of BAECs was altered after 10-day culture with high FFA. Co-culture with protein kinase C (PKC) inhibitors or antioxidants was able to reverse the impairments of receptor agonist-induced NO production and [Ca2+]irises as well as the alteration of receptor affinity in BAECs exposed to FFA. These data indicate that chronic exposure to high FFA reduces NO generation in endothelial cells probably by impairing PLC-mediated Ca2+signaling pathway through activation of PKC and excess generation of oxidants.

scholarly journals Nitric Oxide and Hydrogen Peroxide Signaling in Extractive Shiraia Fermentation by Triton X-100 for Hypocrellin A Production

2020 ◽  
Vol 21 (3) ◽  
pp. 882
Author(s):  
Xin Ping Li ◽  
Yue Wang ◽  
Yan Jun Ma ◽  
Jian Wen Wang ◽  
Li Ping Zheng
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
H2o2 Production ◽  
No Production ◽  
Extractive Fermentation ◽  
Hypocrellin A ◽  
Cell Membrane Permeabilization ◽  
Rapid Generation ◽  
Triton X

Shiraia mycelial culture is a promising biotechnological alternative for the production of hypocrellin A (HA), a new photosensitizer for anticancer photodynamic therapy (PDT). The extractive fermentation of intracellular HA in the nonionic surfactant Triton X-100 (TX100) aqueous solution was studied in the present work. The addition of 25 g/L TX100 at 36 h of the fermentation not only enhanced HA exudation to the broth by 15.6-fold, but stimulated HA content in mycelia by 5.1-fold, leading to the higher production 206.2 mg/L, a 5.4-fold of the control on day 9. After the induced cell membrane permeabilization by TX100 addition, a rapid generation of nitric oxide (NO) and hydrogen peroxide (H2O2) was observed. The increase of NO level was suppressed by the scavenger vitamin C (VC) of reactive oxygen species (ROS), whereas the induced H2O2 production could not be prevented by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), suggesting that NO production may occur downstream of ROS in the extractive fermentation. Both NO and H2O2 were proved to be involved in the expressions of HA biosynthetic genes (Mono, PKS and Omef) and HA production. NO was found to be able to up-regulate the expression of transporter genes (MFS and ABC) for HA exudation. Our results indicated the integrated role of NO and ROS in the extractive fermentation and provided a practical biotechnological process for HA production.

scholarly journals The Nitrite Transporter Facilitates Biofilm Formation via Suppression of Nitrite Reductase and Is a New Antibiofilm Target in Pseudomonas aeruginosa

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Ji-Su Park ◽  
Ha-Young Choi ◽  
Won-Gon Kim
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Nitrite Reductase ◽  
Biofilm Formation ◽  
No Production ◽  
Content Type ◽  
A Genome ◽  
Biofilm Dispersal ◽  
Gmp Production

ABSTRACT Biofilm-forming bacteria, including the Gram-negative Pseudomonas aeruginosa, cause multiple types of chronic infections and are responsible for serious health burdens in humans, animals, and plants. Nitric oxide (NO) has been shown to induce biofilm dispersal via triggering a reduction in cyclic-di-GMP levels in a variety of bacteria. However, how NO, at homeostatic levels, also facilitates biofilm formation is unknown. Here, we found that complestatin, a structural analog of vancomycin isolated from Streptomyces, inhibits P. aeruginosa biofilm formation by upregulating NO production via nitrite reductase (NIR) induction and c-di-GMP degradation via phosphodiesterase (PDE) stimulation. The complestatin protein target was identified as a nitrite transporter from a genome-wide screen using the Keio Escherichia coli knockout library and confirmed using nitrite transporter knockout and overexpression strains. We demonstrated that the nitrite transporter stimulated biofilm formation by controlled NO production via appropriate NIR suppression and subsequent diguanylate cyclase (DGC) activation, not PDE activity, and c-di-GMP production in E. coli and P. aeruginosa. Thus, this study provides a mechanism for NO-mediated biofilm formation, which was previously not understood. IMPORTANCE Bacterial biofilms play roles in infections and avoidance of host defense mechanisms of medically important pathogens and increase the antibiotic resistance of the bacteria. Nitric oxide (NO) is reported to be involved in both biofilm formation and dispersal, which are conflicting processes. The mechanism by which NO regulates biofilm dispersal is relatively understood, but there are no reports about how NO is involved in biofilm formation. Here, by investigating the mechanism by which complestatin inhibits biofilm formation, we describe a novel mechanism for governing biofilm formation in Escherichia coli and Pseudomonas aeruginosa. Nitrite transporter is required for biofilm formation via regulation of NO levels and subsequent c-di-GMP production. Additionally, the nitrite transporter contributes more to P. aeruginosa virulence than quorum sensing. Thus, this study identifies nitrite transporters as new antibiofilm targets for future practical and therapeutic agent development.

Skeletal muscle nitric oxide signaling and exercise: a focus on glucose metabolism

2012 ◽  
Vol 303 (3) ◽  
pp. E301-E307 ◽  
Author(s):  
Glenn K. McConell ◽  
Stephen Rattigan ◽  
Robert S. Lee-Young ◽  
Glenn D. Wadley ◽  
Troy L. Merry
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
Blood Flow ◽  
Glucose Uptake ◽  
No Production ◽  
Nitric Oxide Signaling ◽  
Beneficial Effects ◽  
Low Concentrations ◽  
High Concentrations ◽  
Cellular Components

Nitric oxide (NO) is an important vasodilator and regulator in the cardiovascular system, and this link was the subject of a Nobel prize in 1998. However, NO also plays many other regulatory roles, including thrombosis, immune function, neural activity, and gastrointestinal function. Low concentrations of NO are thought to have important signaling effects. In contrast, high concentrations of NO can interact with reactive oxygen species, causing damage to cells and cellular components. A less-recognized site of NO production is within skeletal muscle, where small increases are thought to have beneficial effects such as regulating glucose uptake and possibly blood flow, but higher levels of production are thought to lead to deleterious effects such as an association with insulin resistance. This review will discuss the role of NO in skeletal muscle during and following exercise, including in mitochondrial biogenesis, muscle efficiency, and blood flow with a particular focus on its potential role in regulating skeletal muscle glucose uptake during exercise.

scholarly journals Production and Consumption of Nitric Oxide by Three Methanotrophic Bacteria

2000 ◽  
Vol 66 (9) ◽  
pp. 3891-3897 ◽  
Author(s):  
Tie Ren ◽  
R�al Roy ◽  
Roger Knowles
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Monoxide ◽  
Pcr Amplification ◽  
No Production ◽  
Anaerobic Conditions ◽  
Methylosinus Trichosporium ◽  
Nitrate Availability ◽  
Group I ◽  
Production And Consumption ◽  
Nitrite Reductases

ABSTRACT We studied nitrogen oxide production and consumption by methanotrophs Methylobacter luteus (group I),Methylosinus trichosporium OB3b (group II), and an isolate from a hardwood swamp soil, here identified by 16S ribosomal DNA sequencing as Methylobacter sp. strain T20 (group I). All could consume nitric oxide (nitrogen monoxide, NO), and produce small amounts of nitrous oxide (N2O). OnlyMethylobacter strain T20 produced large amounts of NO (>250 parts per million by volume [ppmv] in the headspace) at specific activities of up to 2.0 � 10−17 mol of NO cell−1 day−1, mostly after a culture became O2 limited. Production of NO by strain T20 occurred mostly in nitrate-containing medium under anaerobic or nearly anaerobic conditions, was inhibited by chlorate, tungstate, and O2, and required CH4. Denitrification (methanol-supported N2O production from nitrate in the presence of acetylene) could not be detected and thus did not appear to be involved in the production of NO. Furthermore, cd1 and Cu nitrite reductases, NO reductase, and N2O reductase could not be detected by PCR amplification of the nirS,nirK, norB, and nosZ genes, respectively. M. luteus and M. trichosporiumproduced some NO in ammonium-containing medium under aerobic conditions, likely as a result of methanotrophic nitrification and chemical decomposition of nitrite. For Methylobacter strain T20, arginine did not stimulate NO production under aerobiosis, suggesting that NO synthase was not involved. We conclude that strain T20 causes assimilatory reduction of nitrate to nitrite, which then decomposes chemically to NO. The production of NO by methanotrophs such as Methylobacter strain T20 could be of ecological significance in habitats near aerobic-anaerobic interfaces where fluctuating O2 and nitrate availability occur.

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