Nitrification potential in an alder plantation

1984 ◽  
Vol 14 (4) ◽  
pp. 543-546 ◽  
Author(s):  
O. Hendrickson ◽  
L. Chatarpaul
Keyword(s):  
Inhibitory Effect ◽  
Nitrification Potential ◽  
Nitrite Production ◽  
Conifer Needles

Nitrification rates in soil from an alder plantation were measured by nitrite production in chlorate-amended slurries. Rates were stimulated by increased pH, ammonium, and phosphate levels. Alder roots did not have an inhibitory effect on nitrification. Conifer needles totally suppressed nitrite production in the slurries. If conifer needles were added 6 h after the start of incubation, nitrite levels declined rapidly. This decline was attributed to denitrification or microbial assimilation rather than to leakage through the chlorate block.

scholarly journals Soil Nitrification Potential Influences the Performance of Nitrification Inhibitors DCD and DMPP in Cropped and Non-Cropped Soils

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 599
Author(s):  
Hussnain Mukhtar ◽  
Yu-Pin Lin
Keyword(s):  
Inhibitory Effect ◽  
Application Rate ◽  
Major Influence ◽  
Nitrification Inhibitors ◽  
Soil Nitrification ◽  
Beneficial Effects ◽  
Nitrification Potential ◽  
Edaphic Conditions ◽  
Application Rates ◽  
Great Consideration

The application of nitrification inhibitors (NIs) shows promise in prolonging the ammonium presence in soil with beneficial effects for agriculture ecosystems and climate change mitigation. Although the inhibitory effect (IE) of NIs has been studied in the presence of various environmental and edaphic conditions, little is known about the effect of soil nitrification potential (NP) on the effectiveness of NIs. Here, laboratory-scale experiments were conducted to investigate the effect of the variation in soil NP rates, among land-use type and temperature, on the performance of two nitrification inhibitors, dicyandiamide (DCD) and 3,4-dimethypyrazole phosphate (DMPP), at four NI application rates imposed upon eight cropland and non-cropland soils. We found that the IE of DCD and DMPP were organized according to soil NP rates. Nevertheless, NP was lower in non-cropped soil than in cropped systems, and DMPP-based inhibition was higher than DCD. The IE of both NIs decreased with NP and the amount of NI required to achieve an IE ≈ 50%, was significantly reduced for soils that exhibited the lowest NP rates, especially for DMPP. However, the temperature did not appear to have a major influence on IE of both DCD and DMPP, demonstrating the potential of NIs to inhibit nitrification for a wider temperature range, dependent on the NI application rate. Our findings provide evidence that change in soil NP rate has important influences on the efficacy of NI which required great consideration for N-fertilizer optimization with the application of nitrification inhibitors.

Thiopental inhibits nitric oxide production in rat aorta

1999 ◽  
Vol 77 (12) ◽  
pp. 958-966 ◽  
Author(s):  
Carlos Castillo ◽  
Juan Asbun ◽  
Bruno Escalante ◽  
Carlos M Villalón ◽  
Pedro López ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Inhibitory Effect ◽  
Rat Aorta ◽  
Nitric Oxide Production ◽  
Nitric Oxide Synthesis ◽  
Oxide Production ◽  
Nitrite Production ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Endothelium Dependent Relaxation

We studied whether thiopental affects endothelial nitric oxide dependent vasodilator responses and nitrite production (an indicator of nitric oxide production) elicited by acetylcholine, histamine, and A23187 in rat aorta (artery in which nitric oxide is the main endothelial relaxant factor). In addition, we evaluated the barbiturate effect on nitric oxide synthase (NOS) activity in both rat aorta and kidney homogenates. Thiopental (10-100 µg/mL) reversibly inhibited the endothelium-dependent relaxation elicited by acetylcholine, histamine, and A23187. On the contrary, this anesthetic did not modify the endothelium-independent but cGMP-dependent relaxation elicited by sodium nitroprusside (1 nM - 1 µM) and nitroglycerin (1 nM - 1 µM), thus excluding an effect of thiopental on guanylate cyclase of vascular smooth muscle. Thiopental (100 µg/mL) inhibited both basal (87.8 ± 14.3%) and acetylcholine- or A23187-stimulated (78.6 ± 3.9 and 39.7 ± 5.6%, respectively) production of nitrites in aortic rings. In addition the barbiturate inhibited (100 µg/mL) the NOS (45 ± 4 and 42.8 ± 9%) in aortic and kidney homogenates, respectively (measured as 14C-labeled citrulline production). In conclusion, thiopental inhibition of endothelium-dependent relaxation and nitrite production in aortic rings strongly suggests an inhibitory effect on NOS. Thiopental inhibition of the NOS provides further support to this contention.Key words: thiopental, rat aorta, endothelium-dependent relaxation, nitric oxide synthesis.

Cellular regulation of nitrate uptake in denitrifying Flexibacter canadensis

1994 ◽  
Vol 40 (7) ◽  
pp. 576-582 ◽  
Author(s):  
Qitu Wu ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Uptake ◽  
Inhibitory Effect ◽  
Nitrite Reduction ◽  
Nitrite Accumulation ◽  
Cellular Regulation ◽  
Oxygen Inhibition ◽  
Whole Cells ◽  
Nitrite Production ◽  
Carbonyl Cyanide

Nitrate uptake and its regulation were investigated using an ion-specific nitrate electrode for denitrifying Flexibacter canadensis under anaerobic conditions. Glucose supported a greater rate of nitrate uptake than did glycerol, glutamate, lactose, cellobiose, or ethanol. Nitrate uptake closely approximated Michaelis–Menten kinetics; the estimated Ks(glucose) and apparent Km(nitrate) for nitrate uptake were 21 and 44 μM, respectively. Nitrate disappearance was correlated with nitrite accumulation, and nitrate had an inhibitory effect on nitrite reduction. Oxygen inhibition of nitrate uptake increased as the percent air saturation increased, and reversed readily as the percent air saturation decreased. The minimal air saturation showing inhibition of nitrate uptake was about 2–4%. Azide and cyanide completely inhibited nitrate uptake. No nitrate uptake was observed in cells grown in the presence of 1 or 5 mM tungstate (no added molybdate). When molybdate (100–200μM) was present in the medium, nitrate uptake was exhibited by organisms grown with 1 mM, but not with 5 mM, tungstate, indicating that nitrate uptake was dependent on the presence of an active nitrate reductase, and that competition between tungsten and molybdenum occurred during the formation of nitrate reductase. Nitrite production from nitrate by whole cells but not cell-free extracts was inhibited by 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone, indicating that nitrate and (or) nitrite transport depended upon the electrochemical proton gradient.Key words: denitrification, nitrate uptake, Flexibacter canadensis.

scholarly journals Green Pepper (Piper nigrum L.) Extract Suppresses Oxidative Stress and LPS-Induced Inflammation via Regulation of JNK Signaling Pathways

2020 ◽  
Vol 10 (7) ◽  
pp. 2519
Author(s):  
Dae Won Kim ◽  
Min Jeong Kim ◽  
Youngjae Shin ◽  
Sung Keun Jung ◽  
Young-Jun Kim
Keyword(s):  
Sri Lanka ◽  
High Performance ◽  
Radical Scavenging ◽  
Inhibitory Effect ◽  
Black Pepper ◽  
Raw 264.7 Cells ◽  
Piper Nigrum ◽  
Green Pepper ◽  
Inflammatory Stress ◽  
Nitrite Production

In this study, we compared the physicochemical properties and the antioxidant capacities of black and green pepper. Green pepper from India (GPI) and Sri Lanka (GPS) had higher Hunter L* and b* values and lower a* values than black pepper from India (BPI) and Sri Lanka (BPS). The contents of chlorophyll a and b, flavonoids, and phenolic compounds in GPI and GPS were higher than those in BPI and BPS. The peppercorns showed the following decreasing order of 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging capacities: GPI > GPS > BPI > BPS. High-performance liquid chromatography showed that the highest piperine content was present in GPI (8613.27 ± 45.86 mg/100 g). We further investigated the anti-inflammatory capacity of the green pepper. GPS and GPI significantly suppressed lipopolysaccharide (LPS)-induced nitrite production and inducible nitric oxide synthase expression without being cytotoxic to RAW 264.7 cells. GPS and GPI also suppressed the LPS-induced phosphorylation of mitogen-activated protein kinases, but not p65. GPS had a higher inhibitory effect on LPS-induced c-Jun phosphorylation and translocation from the cytosol to the nucleus than GPI. Thus, the findings of our study suggest that green pepper has the potential to be an effective nutraceutical against oxidative and inflammatory stress.

Activation of purinergic P2Y2 receptors inhibits inducible NO synthase in cultured rat mesangial cells

1998 ◽  
Vol 275 (1) ◽  
pp. F103-F110 ◽  
Author(s):  
Markus G. Mohaupt ◽  
Tina Fischer ◽  
Jörg Schwöbel ◽  
R. Bernd Sterzel ◽  
Eckhard Schulze-Lohoff
Keyword(s):  
Mesangial Cells ◽  
Critical Role ◽  
Inhibitory Effect ◽  
Interferon Γ ◽  
Glomerular Injury ◽  
Inos Protein ◽  
P2y2 Receptors ◽  
Nitrite Production ◽  
Inos Protein Expression ◽  
Ifn Γ

Cytokine-induced nitric oxide (NO) is produced on glomerular inflammation. Glomerular injury and thrombocyte aggregation result in the release of nucleotides, which may regulate induced NO synthesis in cultured rat mesangial cells (MCs). ATP (10−3 M) inhibited 24-h nitrite production induced by lipopolysaccharide (LPS, 10 μg/ml)/interferon-γ (IFN-γ, 100 U/ml) by 48.2 ± 6.3%, as well as induction of inducible NOS (iNOS) protein and mRNA. Also, coincubation with either 10−4 M of UTP, ATP, or ATPγS inhibited LPS/IFN-γ-induced nitrite production by 29.9 ± 5.8, 36.4 ± 4.3, and 50.3 ± 6.5%, respectively, indicating involvement of purinergic P2Y2 receptors. Correspondingly, cultured MCs expressed P2Y2 receptor mRNA. Agonists for other purinergic receptors [α,β-methylene-ATP, 3′- O-(4-benzoyl)-benzoyl-ATP, 2-methylthio-ATP, ADP, UDP, adenosine] were ineffective. Treatment with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA, 10−8 M) reproduced the inhibitory effect of ATP on iNOS protein expression and nitrite inhibition (by 46.6 ± 10.4%). The effect of ATP or PMA was reversed by the PKC inhibitors Ro-31-8220 (10−8 M) and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (10−5 M), indicating that suppression of iNOS is mediated via activation of PKC through stimulated P2Y2 receptors. In conclusion, the release of purine mediators may play a critical role for iNOS expression and synthesis of NO during glomerular inflammatory disorders.

Inhibitory effect of trichodermanone C, a sorbicillinoid produced by Trichoderma citrinoviride associated to the green alga Cladophora sp., on nitrite production in LPS-stimulated macrophages

2018 ◽  
Vol 33 (23) ◽  
pp. 3389-3397 ◽  
Author(s):  
Roberta Marra ◽  
Rosario Nicoletti ◽  
Ester Pagano ◽  
Marina DellaGreca ◽  
Maria Michela Salvatore ◽  
...  
Keyword(s):  
Green Alga ◽  
Inhibitory Effect ◽  
Nitrite Production ◽  
Trichoderma Citrinoviride

scholarly journals Inhibitory Effect of Veterinary Antibiotics on Denitrification in Groundwater: A Microcosm Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Mahtab Ahmad ◽  
Meththika Vithanage ◽  
Kangjoo Kim ◽  
Ju-Sik Cho ◽  
Young Han Lee ◽  
...  
Keyword(s):  
Nitrate Removal ◽  
Inhibitory Effect ◽  
Denitrifying Bacteria ◽  
Nitrate Pollution ◽  
Veterinary Antibiotics ◽  
Naturally Occurring ◽  
Nitrite Production ◽  
Microcosm Study ◽  
Maximum Inhibition ◽  
Denitrification Process

Veterinary antibiotics in groundwater may affect natural microbial denitrification process. A microcosm study was conducted to evaluate the influence of sulfamethazine and chlortetracycline at different concentrations (0, 0.01, 0.1, and 1.0 mg/L) on nitrate reduction in groundwater under denitrifying condition. Decrease in nitrate removal and nitrite production was observed with the antibiotics. Maximum inhibition of nitrate removal was observed after seven days of incubation with 0.01 mg/L sulfamethazine (17.0%) and 1.0 mg/L chlortetracycline (15.4%). The nitrite production was inhibited with 1.0 mg/L sulfamethazine to 82.0% and chlortetracycline to 31.1%. The initial/final nitrate concentrations indicated that 0.01 mg/L sulfamethazine and 1.0 mg/L chlortetracycline were most effective in inhibiting activity of denitrifying bacteria in groundwater. After 12 days of incubation, the sulfamethazine biodegradation was observed whereas chlortetracycline was persistent. Sulfamethazine and chlortetracycline in groundwater could inhibit the growth and capability of naturally occurring denitrifying bacteria, thereby threatening nitrate pollution in groundwater.

scholarly journals Insulin inhibits hepatocyte iNOS expression induced by cytokines by an Akt-dependent mechanism

2012 ◽  
Vol 302 (1) ◽  
pp. G116-G122 ◽  
Author(s):  
Brian G. Harbrecht ◽  
Ikenna Nweze ◽  
Jason W. Smith ◽  
Baochun Zhang
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Rat Hepatocytes ◽  
Adenosine Monophosphate ◽  
Inhibitory Effect ◽  
Akt Signaling ◽  
Inos Expression ◽  
Dominant Negative ◽  
Nitrite Accumulation ◽  
Dependent Manner ◽  
Nitrite Production

Hepatocyte inducible nitric oxide synthese (iNOS) expression is a tightly controlled pathway that mediates hepatic inflammation and hepatocyte injury in a variety of disease states. We have shown that cyclic adenosine monophosphate (cAMP) regulates cytokine-induced hepatocyte iNOS expression through mechanisms that involve protein kinase B/Akt. We hypothesized that insulin, which activates Akt signaling in hepatocytes, as well as signaling through p38 and MAPK p42/p44, would regulate iNOS expression during inflammation. In primary rat hepatocytes, insulin inhibited cytokine-stimulated nitrite accumulation and iNOS expression in a dose-dependent manner. Inhibition of MAPK p42/p44 with PD98059 had no effect on iNOS activation, whereas SB203580 to block p38 reversed insulin's inhibitory effect. However, insulin did not increase p38 activation and inhibition of p38 signaling with a dominant negative p38 plasmid had no effect on cytokine- or insulin-mediated effects on iNOS. We found that SB203580 blocked insulin-induced Akt activation. Inhibition of Akt signaling with LY294002 or a dominant negative Akt plasmid increased cytokine-stimulated nitrite production and iNOS protein expression and blocked the inhibitory effects of insulin. NF-κB induces iNOS expression and can be regulated by Akt, but insulin had no effect on cytokine-mediated IκBα levels or NF-κB p65 translocation. Our data demonstrate that insulin inhibits cytokine-stimulated hepatocyte iNOS expression and does so through effects on Akt-mediated signaling.

scholarly journals Bioactive Secondary Metabolites from the Aerial Parts of Buddleja macrostachya

2017 ◽  
Vol 12 (12) ◽  
pp. 1934578X1701201
Author(s):  
Truong Thi Thu Hien ◽  
Tran Hong Quang ◽  
Nguyen Xuan Nhiem ◽  
Bui Huu Tai ◽  
Pham Hai Yen ◽  
...  
Keyword(s):  
Human Cancer ◽  
Radical Scavenging ◽  
Inhibitory Effect ◽  
Major Product ◽  
Human Cancer Cell Lines ◽  
Chemical Structures ◽  
Aerial Parts ◽  
Nitrite Production ◽  
Potent Inhibitory Effect ◽  
Bv2 Microglia

A new iridoid glycoside, buddlemacroside A (1) and 15 known compounds, including 6-α-L-(4″- O-trans-p-coumaroyl)rhamnopyranosylcatalpol (2), 6-α-L-(2″-caffeoyl)rhamnopyranosylcatalpol (3), salidroside (4), echipuroside A (5), darendoside A (6), decaffeoylacteoside (7), acteoside (8), martynoside (9), 8-hydroxylinalool 3- O-β-D-glucopyranoside (10), 9- O-α-L-rhamnopyranosyl-4-hydroxy-cinnamic acid (11), apigenin (12), acacetin-7- O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (13), mimengoside C (14), buddlejasaponin Ia (15), and buddejasaponin I (16) were isolated from a methanol extract of the aerial parts of Buddleja macrostachya Benth. Their chemical structures were elucidated by extensive spectroscopic analyses, including MS and NMR spectra as well as by comparison with the data reported in the literature. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test showed that compounds 3 and 7-9 possess significant scavenging capacity, with SC50 values ranging from 6.9-19.6 μM. Compound 8 was shown to have potent inhibitory effect against the release of malondialdehyde (MDA) - the major product of the cellular lipid peroxidation, with IC50 value of 2.3 μM. Compounds 12 and 16 significantly inhibited nitrite production in LPS-stimulated BV2 microglia, with IC50 values of 14.2 and 11.4 μM, respectively. Furthermore, compound 16 showed cytotoxicity toward three human cancer cell lines, including SK-LU-1, MCF7, HepG2, with IC50 values in the range of 6.5-8.0 μM.

Inhibitory effect of melatonin on nitric oxide synthase in rat enteric nervous system

2001 ◽  
Vol 120 (5) ◽  
pp. A176-A176
Author(s):  
P KOPPITZ ◽  
M STORR ◽  
D SAUR ◽  
M KURJAK ◽  
H ALLESCHER
Keyword(s):  
Nitric Oxide ◽  
Nervous System ◽  
Nitric Oxide Synthase ◽  
Enteric Nervous System ◽  
Inhibitory Effect ◽  
Oxide Synthase
Sign in / Sign up

Export Citation Format

Share Document