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FEBS Letters Feb 1999Peroxynitrite formed in vivo from superoxide and nitric oxide can mediate oxidation, nitration, or nitrosation reactions, leading to impaired function, toxicity, and... (Review)
Review
Peroxynitrite formed in vivo from superoxide and nitric oxide can mediate oxidation, nitration, or nitrosation reactions, leading to impaired function, toxicity, and alterations in signaling pathways. Protection against peroxynitrite is important for defense of normal tissue, especially during inflammation. Biological protection against peroxynitrite is organized in three categories: prevention, interception, and repair. Prevention is the control of the formation of peroxynitrite precursors, nitric oxide and superoxide. Interception is by direct reaction with peroxynitrite, leading to non-toxic products. In this regard, organoselenium compounds, metalloporphyrin derivatives, and peroxidases (e.g. glutathione peroxidase and myeloperoxidase) exhibit high second-order rate constants with peroxynitrite. Ebselen, like glutathione peroxidase, protects in a catalytic fashion utilizing glutathione as reductant in the peroxynitrite reductase reaction. Protection by metalloporphyrins can be maintained through glutathione or ascorbate. Repair processes remove damaged products and restitute intact biomolecules.
Topics: Animals; Humans; Molecular Structure; Nitrates; Oxidants
PubMed: 10094462
DOI: 10.1016/s0014-5793(99)00073-3 -
Experimental Lung Research 2023To investigate the protective effect of p14ARF in a nitric acid (NA) aerosol inhalation-induced bronchiolitis obliterans (BO) mouse model and its potential regulatory...
BACKGROUND
To investigate the protective effect of p14ARF in a nitric acid (NA) aerosol inhalation-induced bronchiolitis obliterans (BO) mouse model and its potential regulatory mechanism.
METHODS
A BO mouse model was established by NA aerosol inhalation. The expressions of p14ARF, phosphatidylinositol-3-kinase (PI3K), and protein kinase B (AKT) were detected by quantitative reverse transcription PCR (qRT-PCR) and western blot (WB). Hematoxylin (HE) staining, Masson staining, and periodic acid-Schiff (PAS) staining observed pulmonary histological changes. TdT-mediated dUTP nick end labeling (TUNEL) staining detected pulmonary cell apoptosis, and enzyme-linked immunosorbent assay (ELISA) measured matrix metalloproteinase-2 (MMP-2), MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), interleukon-6 (IL-6), and transforminh growth factor-β (TGF-β) levels in lung tissue and bronchoalveolar lavage fluid (BALF).
RESULTS
The expressions of p14ARF, PI3K, and AKT showed a time gradient change, with a decrease trend (*P < 0.05 and **P < 0.01). Severe inflammatory infiltration and tracheal fibrosis were found in lung tissue in the modeling group (BO group) compared with the control group (Con group). The pH, PaO, and PaO/FiO values significantly reduced, while the PaCO value and the number of TUNEL-positive cells increased in BO group (P < 0.05). In addition, MMP-2, MMP-9, IL-6, and TGF-β levels remarkably increased, with an increase in the number of white blood cells, neutrophils, and lymphocytes in BO group (P < 0.05). Furthermore, p14ARF up-regulation reversed the trend of the aforementioned indexes in BO mice.
CONCLUSIONS
p14ARF ameliorated the inflammatory response and airway remodeling in a BO mouse model via the PI3K/AKT pathway.
Topics: Mice; Animals; Matrix Metalloproteinase 2; Proto-Oncogene Proteins c-akt; Tumor Suppressor Protein p14ARF; Nitric Acid; Matrix Metalloproteinase 9; Phosphatidylinositol 3-Kinases; Airway Remodeling; Tissue Inhibitor of Metalloproteinase-1; Interleukin-6; Respiratory Aerosols and Droplets; Bronchiolitis Obliterans; Inflammation; Transforming Growth Factor beta; Disease Models, Animal
PubMed: 36621972
DOI: 10.1080/01902148.2022.2163322 -
Annual Review of Marine Science Jan 2024The genus is globally distributed, with blooms commonly occurring on continental shelves. This unusual phytoplankter has two major morphologies: solitary cells and... (Review)
Review
The genus is globally distributed, with blooms commonly occurring on continental shelves. This unusual phytoplankter has two major morphologies: solitary cells and cells embedded in a gelatinous matrix. Only colonies form blooms. Their large size (commonly 2 mm but up to 3 cm) and mucilaginous envelope allow the colonies to escape predation, but data are inconsistent as to whether colonies are grazed. Cultured can also inhibit the growth of co-occurring phytoplankton or the feeding of potential grazers. Colonies and solitary cells use nitrate as a nitrogen source, although solitary cells can also grow on ammonium. colonies might be a major contributor to carbon flux to depth, but in most cases, colonies are rapidly remineralized in the upper 300 m. The occurrence of large blooms is often associated with environments with low and highly variable light and high nitrate levels, with blooms being linked additionally to high iron availability. Emerging results indicate that different clones of have substantial genetic plasticity, which may explain its appearance in a variety of environments. Given the evidence of appearing in new systems, this trend will likely continue in the near future.
Topics: Haptophyta; Nitrates; Phytoplankton; Eutrophication
PubMed: 37647611
DOI: 10.1146/annurev-marine-022223-025031 -
Proceedings of the National Academy of... Aug 2021Recent research [Wang , 581, 184-189 (2020)] indicates nitric acid (NA) can participate in sulfuric acid (SA)-ammonia (NH) nucleation in the clean and cold upper free...
Recent research [Wang , 581, 184-189 (2020)] indicates nitric acid (NA) can participate in sulfuric acid (SA)-ammonia (NH) nucleation in the clean and cold upper free troposphere, whereas NA exhibits no obvious effects at the boundary layer with relatively high temperatures. Herein, considering that an SA-dimethylamine (DMA) nucleation mechanism was detected in megacities [Yao , 361, 278-281 (2018)], the roles of NA in SA-DMA nucleation are investigated. Different from SA-NH nucleation, we found that NA can enhance SA-DMA-based particle formation rates in the polluted atmospheric boundary layer, such as Beijing in winter, with the enhancement up to 80-fold. Moreover, we found that NA can promote the number concentrations of nucleation clusters (up to 27-fold) and contribute 76% of cluster formation pathways at 280 K. The enhancements on particle formation by NA are critical for particulate pollution in the polluted boundary layer with relatively high NA and DMA concentrations.
Topics: Ammonia; Atmosphere; Dimethylamines; Environmental Pollutants; Environmental Pollution; Models, Chemical; Nitric Acid; Sulfuric Acids; Thermodynamics
PubMed: 34453007
DOI: 10.1073/pnas.2108384118 -
International Journal of Environmental... Dec 2021Onychomycosis is the main cause of toenail disorders and is produced by a fungal infection. It is becoming more prevalent because of new lifestyles and immunosuppression...
UNLABELLED
Onychomycosis is the main cause of toenail disorders and is produced by a fungal infection. It is becoming more prevalent because of new lifestyles and immunosuppression statuses. The therapeutic approach to onychomycosis is under considerable study because of the lengthy treatments that require strong patient commitment, the limited efficacy of treatments, the inclusion of active substances that can be hepatotoxic and cause pharmacological interactions, and/or the questionable efficacy of treatments due to a lack of clinical trials. This study responds to the demand for rapid treatment with minimal pharmacological interactions.
METHODS
The efficacy of nitric acid 60% treatment in patients with onychomycosis was monitored and studied. The antifungal efficacy of nitric acid was measured by microbiological culture before and after treatment and the clinical evolution of nail dystrophy was quantitatively measured by monitoring with the Onychomycosis Severity Index (OSI).
RESULTS
The results show that, with the protocol used, nitric acid 60% painlessly cured 40% (microbiologic cure) of the cases treated, and in all cases, clinical improvement was observed ( = 0.011).
CONCLUSIONS
The treatment with nitric acid 60% is as efficient as conventional treatments, requires less patient compliance of the treatment and produces no pharmacological interactions, providing alternative treatment in the case of hepatotoxicity.
Topics: Antifungal Agents; Foot Dermatoses; Humans; Nails; Nitric Acid; Onychomycosis; Treatment Outcome
PubMed: 34948980
DOI: 10.3390/ijerph182413371 -
Bioelectrochemistry (Amsterdam,... Aug 2023Bioelectrochemical systems which employ microbes as electrode catalysts to convert chemical energy into electrical energy (or conversely), have emerged in recent years... (Review)
Review
Bioelectrochemical systems which employ microbes as electrode catalysts to convert chemical energy into electrical energy (or conversely), have emerged in recent years for water sanitation and energy recovery. Microbial biocathodes, and especially those reducing nitrate are gaining more and more attention. The nitrate-reducing biocathodes can efficiently treat nitrate-polluted wastewater. However, they require specific conditions and they have not yet been applied on a large scale. In this review, the current knowledge on nitrate-reducing biocathodes will be summarized. The fundamentals of microbial biocathodes will be discussed, as well as the progress towards applications for nitrate reduction in the context of water treatment. Nitrate-reducing biocathodes will be compared with other nitrate-removal techniques and the challenges and opportunities of this approach will be identified.
Topics: Nitrates; Electricity; Wastewater; Electrodes; Water Purification; Bioelectric Energy Sources
PubMed: 37099858
DOI: 10.1016/j.bioelechem.2023.108436 -
Environmental Health Perspectives Aug 1974Extensive ambient extraction of several metals from human hair compromises some assumptions concerning the binding of metals to hair and the biochemical process of metal...
Extensive ambient extraction of several metals from human hair compromises some assumptions concerning the binding of metals to hair and the biochemical process of metal incorporation into hair. Hair metal concentrations can reveal metal intoxications and metal deficiencies.The scalp hair selected for investigation included specimens of different colors from both sexes for various donor ages and from different geographic exposure areas. The hair samples were washed by agitation for 30 min with a 1% solution of sodium lauryl sulfate in a pH 7.2 buffer, rinsed repeatedly with deionized water, and oven-dried at 110 degrees C before 2-g portions were taken for extraction and digestion. Extraction involved agitation of the washed hair samples for 21 hr with 40 ml of 1% nitric acid at room temperature (23 degrees C). The extracted hair was digested in order to quantitate the amount of metal that was not extracted. Metal measurements were made by conventional flame atomic absorption spectroscopy. Potential interferences were investigated. Extraction varied between 82 and 100% for Na, Mg, K, Ca, Mn, Zn, Cd, and Pb. Removal of Fe, Ni, and Cu was 33-54%. Anatomical location, binding chemistry, biochemical incorporation, and mass screening are discussed.
Topics: Adolescent; Adult; Binding Sites; Child; Color; Female; Hair; Humans; Male; Metals; Middle Aged; Nitrates; Perchlorates; Scalp; Sodium Dodecyl Sulfate; Spectrophotometry, Atomic; Trace Elements
PubMed: 4377869
DOI: 10.1289/ehp.748191 -
PloS One 2016Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture....
Nitrohumic acids, produced from base extraction of coals and peats oxidized with nitric acid, have received considerable attention as soil ammendments in agriculture. The nitration chemistry however is incompletely understood. Moreover, there is a need to understand the reaction of nitric acid with natural organic matter (NOM) in general, in the context of a variety of environmental and biogeochemical processes. Suwannee River NOM, Suwannee River fulvic acid, and Pahokee Peat fulvic acid were treated with 15N-labeled nitric acid at concentrations ranging from 15% to 22% and analyzed by liquid and solid state 15N NMR spectroscopy. Bulk Pahokee peat and Illinois #6 coal were also treated with nitric acid, at 29% and 40% respectively, and analyzed by solid state 15N NMR spectroscopy. In addition to nitro groups from nitration of aromatic carbon, the 15N NMR spectra of all five samples exhibited peaks attributable to nitrosation reactions. These include nitrosophenol peaks in the peat fulvic acid and Suwannee River samples, from nitrosation of phenolic rings, and N-nitroso groups in the peat samples, from nitrosation of secondary amides or amines, the latter consistent with the peat samples having the highest naturally abundant nitrogen contents. Peaks attributable to Beckmann and secondary reactions of the initially formed oximes were present in all spectra, including primary amide, secondary amide, lactam, and nitrile nitrogens. The degree of secondary reaction product formation resulting from nitrosation reactions appeared to correlate inversely with the 13C aromaticities of the samples. The nitrosation reactions are most plausibly effected by nitrous acid formed from the reduction of nitric acid by oxidizable substrates in the NOM and coal samples.
Topics: Benzopyrans; Carbon Isotopes; Carbon-13 Magnetic Resonance Spectroscopy; Coal; Elements; Nitric Acid; Nitrosation; Soil
PubMed: 27175784
DOI: 10.1371/journal.pone.0154981 -
Chemical & Pharmaceutical Bulletin 2021This study aimed to investigate the characteristics of acid-activated bentonite by focusing on its capability of improving the quality of tap water used during wire...
This study aimed to investigate the characteristics of acid-activated bentonite by focusing on its capability of improving the quality of tap water used during wire electrical discharge machining. Raw bentonite (RB) was activated using sulfuric acid, nitric acid, and phosphoric acid solutions with concentrations of 1, 5, and 10 mol/L, respectively. Scanning electron microscopy images, specific surface area, pore volume, cation exchange capacity, X-ray diffraction patterns, and binding energy of RB and acid-activated bentonites were also evaluated. The specific surface area and pore volume of acid-activated bentonites exceeded those of RB. Conversely, the cation exchange capacity of acid-activated bentonites exhibited an opposite trend. The electrical conductivity of tap water was decreased significantly due to bentonite activated with sulfuric acid, nitric acid, and phosphoric acid solution (removal percentage of approximately 31-39%), as compared to that due to RB. Therefore, the relationship between electrical conductivity and the removed concentration of anion/cation ions was evaluated; the correlation coefficient was -0.950 for the experimental condition in this study. Additionally, the amount of magnesium, calcium, potassium, and sodium ions were decreased after the treatment. These results indicated that acid-activated bentonite can be produced from RB via acid activation and that it can be used to decrease electrical conductivity of tap water.
Topics: Bentonite; Electric Conductivity; Nitric Acid; Particle Size; Phosphoric Acids; Quality Control; Solutions; Sulfuric Acids; Water
PubMed: 33390526
DOI: 10.1248/cpb.c20-00703 -
Journal of Experimental Botany Jul 2020The enzymatic controlled metabolic processes in cells occur at their optimized pH ranges, therefore cellular pH homeostasis is fundamental for life. In plants, the... (Review)
Review
The enzymatic controlled metabolic processes in cells occur at their optimized pH ranges, therefore cellular pH homeostasis is fundamental for life. In plants, the nitrogen (N) source for uptake and assimilation, mainly in the forms of nitrate (NO3-) and ammonium (NH4+) quantitatively dominates the anion and cation equilibrium and the pH balance in cells. Here we review ionic and pH homeostasis in plant cells and regulation by N source from the rhizosphere to extra- and intracellular pH regulation for short- and long-distance N distribution and during N assimilation. In the process of N transport across membranes for uptake and compartmentation, both proton pumps and proton-coupled N transporters are essential, and their proton-binding sites may sense changes of apoplastic or intracellular pH. In addition, during N assimilation, carbon skeletons are required to synthesize amino acids, thus the combination of NO3- or NH4+ transport and assimilation results in different net charge and numbers of protons in plant cells. Efficient maintenance of N-controlled cellular pH homeostasis may improve N uptake and use efficiency, as well as enhance the resistance to abiotic stresses.
Topics: Ammonium Compounds; Homeostasis; Hydrogen-Ion Concentration; Nitrates; Nitrogen; Plant Physiological Phenomena
PubMed: 32206788
DOI: 10.1093/jxb/eraa150