-
Scientific Reports Jun 2022MPO-derived oxidants including HOCl contribute to tissue damage and the initiation and propagation of inflammatory diseases. The search for small molecule inhibitors of...
MPO-derived oxidants including HOCl contribute to tissue damage and the initiation and propagation of inflammatory diseases. The search for small molecule inhibitors of myeloperoxidase, as molecular tools and potential drugs, requires the application of high throughput screening assays based on monitoring the activity of myeloperoxidase. In this study, we have compared three classes of fluorescent probes for monitoring myeloperoxidase-derived hypochlorous acid, including boronate-, aminophenyl- and thiol-based fluorogenic probes and we show that all three classes of probes are suitable for this purpose. However, probes based on the coumarin fluorophore turned out to be not reliable indicators of the inhibitors' potency. We have also determined the rate constants of the reaction between HOCl and the probes and they are equal to 1.8 × 10 Ms for coumarin boronic acid (CBA), 1.1 × 10 Ms for fluorescein based boronic acid (FLBA), 3.1 × 10 Ms for 7-(p-aminophenyl)-coumarin (APC), 1.6 × 10 Ms for 3'-(p-aminophenyl)-fluorescein (APF), and 1 × 10 Ms for 4-thiomorpholino-7-nitrobenz-2-oxa-1,3-diazole (NBD-TM). The high reaction rate constant of NBD-TM with HOCl makes this probe the most reliable tool to monitor HOCl formation in the presence of compounds showing HOCl-scavenging activity.
Topics: Boronic Acids; Coumarins; Fluoresceins; Fluorescent Dyes; Hypochlorous Acid; Peroxidase
PubMed: 35660769
DOI: 10.1038/s41598-022-13317-8 -
Ecotoxicology and Environmental Safety Sep 2022Co-invasion by two invasive plant species (IPS) can occur in the same habitat. Diversified acid deposition may change the co-invasion process by altering litter...
Co-invasion by two invasive plant species (IPS) can occur in the same habitat. Diversified acid deposition may change the co-invasion process by altering litter decomposition and plant-soil feedback signalling. This study examined the co-decomposition of two Asteraceae IPS (Solidago canadensis L. and Bidens pilosa L.) on litter decomposition rate, soil enzyme activities, and soil N-fixing bacterial communities under diversified acid deposition (mixed acid deposition at pH 5.6 and at pH 4.5, sulfuric acid at pH 4.5, and nitric acid at pH 4.5). B. pilosa litter degraded faster than S. canadensis litter. Acid deposition at higher acidity accelerated the decomposition rate of both pure S. canadensis litter and the equally mixed litters from the two Asteraceae IPS. Antagonistic responses may occur during the co-decomposition of the two Asteraceae IPS with mixed acid deposition, regardless of the pH, as well as with nitric acid deposition at pH 4.5; in contrast, there may be neutral responses for the co-decomposition process with sulfuric acid at pH 4.5. The type of acid deposited may be one of the key factors affecting the intensity of the mixing effect affecting the co-decomposition. Acid deposition at higher acidity weakened the antagonistic responses for the co-decomposition of the two Asteraceae IPS compared with the response to weak acids. Together, these results indicate that acid deposition at higher acidity could facilitate the co-invasion of the two Asteraceae IPS mainly through accelerated litter decomposition as well as weakened antagonistic responses for co-decomposition.
Topics: Asteraceae; Ecosystem; Introduced Species; Nitric Acid; Plant Leaves; Plants; Soil; Solidago; Sulfuric Acids
PubMed: 36030689
DOI: 10.1016/j.ecoenv.2022.114012 -
Molecules (Basel, Switzerland) Aug 2020This review covers the main synthetic routes to and the corresponding mechanisms of phosphoramidate formation. The synthetic routes can be separated into six categories:... (Review)
Review
This review covers the main synthetic routes to and the corresponding mechanisms of phosphoramidate formation. The synthetic routes can be separated into six categories: salt elimination, oxidative cross-coupling, azide, reduction, hydrophosphinylation, and phosphoramidate-aldehyde-dienophile (PAD). Examples of some important compounds synthesized through these routes are provided. As an important class of organophosphorus compounds, the applications of phosphoramidate compounds, are also briefly introduced.
Topics: Amides; Chemistry Techniques, Synthetic; Phosphoric Acids
PubMed: 32823507
DOI: 10.3390/molecules25163684 -
Journal of Visualized Experiments : JoVE Oct 2017We present the synthesis of (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid as an example to demonstrate a method for the synthesis of high purity...
We present the synthesis of (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid as an example to demonstrate a method for the synthesis of high purity nonsymmetric dialkylphosphinic acid extractants. Low toxic sodium hypophosphite was chosen as the phosphorus source to react with olefin A (2,3-dimethyl-1-butene) to generate a monoalkylphosphinic acid intermediate. Amantadine was adopted to remove the dialkylphosphinic acid byproduct, as only the monoalkylphosphinic acid can react with amantadine to form an amantadine∙mono-alkylphosphinic acid salt, while the dialkylphosphinic acid cannot react with amantadine due to its large steric hindrance. The purified monoalkylphosphinic acid was then reacted with olefin B (diisobutylene) to yield nonsymmetric dialkylphosphinic acid (NSDAPA). The unreacted monoalkylphosphinic acid can be easily removed by a simple base-acid post-treatment and other organic impurities can be separated out through the precipitation of the cobalt salt. The structure of the (2,3-dimethylbutyl)(2,4,4'-trimethylpentyl)phosphinic acid was confirmed by P NMR, H NMR, ESI-MS, and FT-IR. The purity was determined by a potentiometric titration method, and the results indicate that the purity can exceed 96%.
Topics: Magnetic Resonance Spectroscopy; Phosphinic Acids
PubMed: 29155717
DOI: 10.3791/56156 -
Molecules (Basel, Switzerland) Sep 2014Acid catalysis is quite prevalent and probably one of the most routine operations in both industrial processes and research laboratories worldwide. Recently, "graphene",... (Review)
Review
Acid catalysis is quite prevalent and probably one of the most routine operations in both industrial processes and research laboratories worldwide. Recently, "graphene", a two dimensional single-layer carbon sheet with hexagonal packed lattice structure, imitative of nanomaterials, has shown great potential as alternative and eco-friendly solid carbocatalyst for a variety of acid-catalyzed reactions. Owing to their exceptional physical, chemical, and mechanical properties, graphene-based nanomaterials (G-NMs) offer highly stable Brønsted acidic sites, high mass transfer, relatively large surface areas, water tolerant character, and convenient recoverability as well as recyclability, whilst retaining high activity in acid-catalyzed chemical reactions. This comprehensive review focuses on the chemistry of G-NMs, including their synthesis, characterization, properties, functionalization, and up-to-date applications in heterogeneous acid catalysis. In line with this, in certain instances readers may find herein some criticisms that should be taken as constructive and would be of value in understanding the scope and limitations of current approaches utilizing graphene and its derivatives for the same.
Topics: Acids; Catalysis; Graphite; Green Chemistry Technology; Nanostructures
PubMed: 25225721
DOI: 10.3390/molecules190914582 -
Antimicrobial Agents and Chemotherapy Sep 2023Taniborbactam and xeruborbactam are dual serine-/metallo-beta-lactamase inhibitors (BLIs) based on a cyclic boronic acid pharmacophore that undergo clinical development....
Taniborbactam and xeruborbactam are dual serine-/metallo-beta-lactamase inhibitors (BLIs) based on a cyclic boronic acid pharmacophore that undergo clinical development. Recent report demonstrated that New Delhi metallo-beta-lactamase (NDM)-9 (differs from NDM-1 by a single amino acid substitution, E152K, evolved to overcome Zn (II) deprivation) is resistant to inhibition by taniborbactam constituting pre-existing taniborbactam resistance mechanism. Using microbiological and biochemical experiments, we show that xeruborbactam is capable of inhibiting NDM-9 and propose the structural basis for differences between two BLIs.
Topics: Amino Acid Substitution; Borinic Acids; Boronic Acids; beta-Lactam Resistance; beta-Lactamase Inhibitors
PubMed: 37650617
DOI: 10.1128/aac.00579-23 -
Molecules (Basel, Switzerland) Nov 2019Fractionation of lignocellulose is a fundamental step in the valorization of cellulose, hemicelluloses, and lignin to produce various sustainable fuels and chemicals.... (Review)
Review
Fractionation of lignocellulose is a fundamental step in the valorization of cellulose, hemicelluloses, and lignin to produce various sustainable fuels and chemicals. Mineral acid fractionation is one of the most applied process and leads to the solubilization and hydrolysis of cellulose and hemicelluloses, whereas most of the lignin remains insoluble and can be separated from the extract. The obtained monomeric sugars in the acid extract are in solution with salts, sugar degradation products, and phenolic molecules. Downstream processing is required to purify the sugars and further valorize them into fuels or chemicals with the use of chemical or biochemical reactions. This purification step also allows the recycling of the mineral acid and the valorization of the sugar degradation products and the co-extracted phenolic molecules, adding value to the whole biorefinery scheme. Many purification techniques have been studied, providing several options in terms of yields, purities, and cost of the process. This review presents the conditions used for the mineral acid fractionation step and a wide variety of purification techniques applied on the obtained hydrolysate, with a focus on the associated yields and purities. Values from the literature are expressed in a standard way in order to simplify comparison between the different processes.
Topics: Acids; Biomass; Chemical Fractionation; Hydrolysis; Lignin; Minerals
PubMed: 31771199
DOI: 10.3390/molecules24234273 -
FEMS Microbiology Reviews Jan 2003Fluoride is widely used as an anticaries agent in drinking water and a variety of other vehicles. This use has resulted in major health benefits. However, there are... (Review)
Review
Fluoride is widely used as an anticaries agent in drinking water and a variety of other vehicles. This use has resulted in major health benefits. However, there are still open questions regarding the mechanisms of anticaries action and the importance of antimicrobial effects in caries reduction. Fluoride acts in multiple ways to affect the metabolism of cariogenic and other bacteria in the mouth. F(-)/HF can bind directly to many enzymes, for example, heme-containing enzymes or other metalloenzymes, to modulate metabolism. Fluoride is able also to form complexes with metals such as aluminum or beryllium, and the complexes, notably AlF(4)(-) and BeF(3)(-).H(2)O, can mimic phosphate with either positive or negative effects on a variety of enzymes and regulatory phosphatases. The fluoride action that appears to be most important for glycolytic inhibition at low pH in dental plaque bacteria derives from its weak-acid properties (pK(a)=3.15) and the capacity of HF to act as a transmembrane proton conductor. Since many of the actions of fluoride are related to its weak-acid character, it is reasonable to compare fluoride action to those of organic weak acids, including metabolic acids, food preservatives, non-steroidal anti-inflammatory agents and fatty acids, all of which act to de-energize the cell membrane by discharging DeltapH. Moreover, with the realization that the biofilm state is the common lifestyle for most microorganisms in nature, there is need to consider interactions of fluoride and organic weak acids with biofilm communities. Hopefully, this review will stimulate interest in the antimicrobial effects of fluoride or other weak acids and lead to more effective use of the agents for disease control and other applications.
Topics: Acids; Bacteria; Bacterial Physiological Phenomena; Biofilms; Cariostatic Agents; Dental Caries; Fatty Acids; Fluorides; Hydrogen-Ion Concentration; Organic Chemicals; Streptococcus mutans
PubMed: 12586392
DOI: 10.1111/j.1574-6976.2003.tb00627.x -
Medycyna Pracy Sep 2022The presence of inorganic acids in the air poses a threat to the health of workers. Volatile inorganic acids, e.g., hydrochloric acid, hydrobromic acid and nitric acid,...
BACKGROUND
The presence of inorganic acids in the air poses a threat to the health of workers. Volatile inorganic acids, e.g., hydrochloric acid, hydrobromic acid and nitric acid, may cause respiratory, eye and skin irritation. The presented method uses ion chromatography to determine the concentrations of hydrochloric, hydrobromic and nitric acids in air samples.
MATERIAL AND METHODS
The method is based on the collection of airborne volatile acids on impregnated quartz fiber filter, extraction of acids with deionized water, and analysis by ion chromatography with conductivity suppression. The separation was performed on the Dionex IonPac™ AS22 (4 × 250 mm) column for trace anion analysis. The carbonate/bicarbonate eluent was maintained at an isocratic flow rate of 1.2 ml/min. The calibration standard solutions have been covering the range of 0.2-5 mg/l of chloride, bromide and nitrate.
RESULTS
The specified chromatographic conditions enable selective measurement of chloride, bromide and nitrate anions. The obtained mass concentration of each anion, having factored in the sample dilution, the conversion factor (to convert anion concentration to acid) and the volume of the air sample, allows the calculation of acid concentrations in the analyzed air.
CONCLUSIONS
This method makes it possible to determine the concentration of hydrochloric acid, hydrobromic acid and nitric acid in the workplace air within the concentration range corresponding to 0.1-2 times the exposure limit value in Poland. The method meets the criteria for the performance of procedures for the measurement of chemical agents, listed in PN-EN 482. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering. Med Pr. 2022;73(4):337-47.
Topics: Air Pollutants, Occupational; Anions; Bromides; Chlorides; Chromatography; Environmental Monitoring; Humans; Hydrobromic Acid; Hydrochloric Acid; Nitrates; Nitric Acid; Workplace
PubMed: 35912840
DOI: 10.13075/mp.5893.01226 -
Applied and Environmental Microbiology Sep 2019Contamination by fungi may pose a threat to the long-term operation of the International Space Station because fungi produce organic acids that corrode equipment and...
Contamination by fungi may pose a threat to the long-term operation of the International Space Station because fungi produce organic acids that corrode equipment and mycotoxins that harm human health. Microgravity is an unavoidable and special condition in the space station. However, the influence of microgravity on fungal metabolism has not been well studied. Clinostat rotation is widely used to simulate the microgravity condition in studies carried out on Earth. Here, we used metabolomics differential analysis to study the influence of clinostat rotation on the accumulation of organic acids and related biosynthetic pathways in ochratoxin A (OTA)-producing As a result, clinostat rotation did not affect fungal cell growth or colony appearance but significantly increased the accumulation of organic acids, particularly isocitric acid, citric acid, and oxalic acid, and OTA both inside cells and in the medium, as well as resulted in a much higher level of accumulation of some products inside than outside cells, indicating that the transport of these metabolites from the cell to the medium was inhibited. This finding corresponded to the change in the fatty acid composition of cell membranes and the reduced thickness of the cell walls and cell membranes. Amino acid and energy metabolic pathways, particularly the tricarboxylic acid cycle, were influenced the most during clinostat rotation compared to the effects of normal gravity on these pathways. Fungi are ubiquitous in nature and have the ability to corrode various materials by producing metabolites. Research on how the space station environment, especially microgravity, affects fungal metabolism is helpful to understand the role of fungi in the space station. This work provides insights into the mechanisms involved in the metabolism of the corrosive fungus under simulated microgravity conditions. Our findings have significance not only for preventing material corrosion but also for ensuring food safety, especially in the space environment.
Topics: Acids; Aspergillus; Biosynthetic Pathways; Metabolomics; Ochratoxins; Weightlessness
PubMed: 31300399
DOI: 10.1128/AEM.01023-19