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British Dental Journal Jul 2020
Topics: Fluorides, Topical; Quaternary Ammonium Compounds; Silver Compounds
PubMed: 32651490
DOI: 10.1038/s41415-020-1905-z -
Journal of Visualized Experiments : JoVE Jan 2015Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an...
Streams such as urine and manure can contain high levels of ammonium, which could be recovered for reuse in agriculture or chemistry. The extraction of ammonium from an ammonium-rich stream is demonstrated using an electrochemical and a bioelectrochemical system. Both systems are controlled by a potentiostat to either fix the current (for the electrochemical cell) or fix the potential of the working electrode (for the bioelectrochemical cell). In the bioelectrochemical cell, electroactive bacteria catalyze the anodic reaction, whereas in the electrochemical cell the potentiostat applies a higher voltage to produce a current. The current and consequent restoration of the charge balance across the cell allow the transport of cations, such as ammonium, across a cation exchange membrane from the anolyte to the catholyte. The high pH of the catholyte leads to formation of ammonia, which can be stripped from the medium and captured in an acid solution, thus enabling the recovery of a valuable nutrient. The flux of ammonium across the membrane is characterized at different anolyte ammonium concentrations and currents for both the abiotic and biotic reactor systems. Both systems are compared based on current and removal efficiencies for ammonium, as well as the energy input required to drive ammonium transfer across the cation exchange membrane. Finally, a comparative analysis considering key aspects such as reliability, electrode cost, and rate is made. This video article and protocol provide the necessary information to conduct electrochemical and bioelectrochemical ammonia recovery experiments. The reactor setup for the two cases is explained, as well as the reactor operation. We elaborate on data analysis for both reactor types and on the advantages and disadvantages of bioelectrochemical and electrochemical systems.
Topics: Ammonium Compounds; Electrochemical Techniques; Electrodes; Hydrogen-Ion Concentration; Reproducibility of Results; Wastewater
PubMed: 25651406
DOI: 10.3791/52405 -
International Journal of Molecular... Oct 2020Nitrogen (N) is an essential nutrient for plant growth and development. Plant species respond to N fluctuations and N sources, i.e., ammonium or nitrate, differently....
Nitrogen (N) is an essential nutrient for plant growth and development. Plant species respond to N fluctuations and N sources, i.e., ammonium or nitrate, differently. Masson pine ( Lamb.) is one of the pioneer plants in the southern forests of China. It shows better growth when grown in medium containing ammonium as compared to nitrate. In this study, we had grown masson pine seedlings in medium containing ammonium, nitrate, and a mixture of both, and performed comparative transcriptome and proteome analyses to observe the differential signatures. Our transcriptome and proteome resulted in the identification of 1593 and 71 differentially expressed genes and proteins, respectively. Overall, the masson pine roots had better performance when fed with a mixture of ammonium and nitrate. The transcriptomic and proteomics results combined with the root morphological responses suggest that when ammonium is supplied as a sole N-source to masson pine seedlings, the expression of ammonium transporters and other non-specific NH-channels increased, resulting in higher NH concentrations. This stimulates lateral roots branching as evidenced from increased number of root tips. We discussed the root performance in association with ethylene responsive transcription factors, WRKYs, and MADS-box transcription factors. The differential analysis data suggest that the adaptability of roots to ammonium is possibly through the promotion of TCA cycle, owing to the higher expression of malate synthase and malate dehydrogenase. Masson pine seedlings managed the increased NH influx by rerouting N resources to asparagine production. Additionally, flavonoid biosynthesis and flavone and flavonol biosynthesis pathways were differentially regulated in response to increased ammonium influx. Finally, changes in the glutathione s-transferase genes suggested the role of glutathione cycle in scavenging the possible stress induced by excess NH. These results demonstrate that masson pine shows increased growth when grown under ammonium by increased N assimilation. Furthermore, it can tolerate high NH content by involving asparagine biosynthesis and glutathione cycle.
Topics: Ammonium Compounds; Gene Expression Regulation, Plant; Nitrates; Pinus; Plant Roots; Proteome; Seedlings; Transcriptome
PubMed: 33066140
DOI: 10.3390/ijms21207548 -
Chemistry (Weinheim An Der Bergstrasse,... Jan 2021C(1)-Ammonium enolates are powerful, catalytically generated synthetic intermediates applied in the enantioselective α-functionalisation of carboxylic acid derivatives.... (Review)
Review
C(1)-Ammonium enolates are powerful, catalytically generated synthetic intermediates applied in the enantioselective α-functionalisation of carboxylic acid derivatives. This minireview describes the recent developments in the generation and application of C(1)-ammonium enolates from various precursors (carboxylic acids, anhydrides, acyl imidazoles, aryl esters, α-diazoketones, alkyl halides) using isothiourea Lewis base organocatalysts. Their synthetic utility in intra- and intermolecular enantioselective C-C and C-X bond forming processes on reaction with various electrophiles will be showcased utilising two distinct catalyst turnover approaches.
Topics: Ammonium Compounds; Carboxylic Acids; Catalysis; Molecular Structure; Stereoisomerism
PubMed: 32557875
DOI: 10.1002/chem.202002059 -
Plant Cell Reports Dec 2022Elevated methylglyoxal levels contribute to ammonium-induced growth disorders in Arabidopsis thaliana. Methylglyoxal detoxification pathway limitation, mainly the...
Elevated methylglyoxal levels contribute to ammonium-induced growth disorders in Arabidopsis thaliana. Methylglyoxal detoxification pathway limitation, mainly the glyoxalase I activity, leads to enhanced sensitivity of plants to ammonium nutrition. Ammonium applied to plants as the exclusive source of nitrogen often triggers multiple phenotypic effects, with severe growth inhibition being the most prominent symptom. Glycolytic flux increase, leading to overproduction of its toxic by-product methylglyoxal (MG), is one of the major metabolic consequences of long-term ammonium nutrition. This study aimed to evaluate the influence of MG metabolism on ammonium-dependent growth restriction in Arabidopsis thaliana plants. As the level of MG in plant cells is maintained by the glyoxalase (GLX) system, we analyzed MG-related metabolism in plants with a dysfunctional glyoxalase pathway. We report that MG detoxification, based on glutathione-dependent glyoxalases, is crucial for plants exposed to ammonium nutrition, and its essential role in ammonium sensitivity relays on glyoxalase I (GLXI) activity. Our results indicated that the accumulation of MG-derived advanced glycation end products significantly contributes to the incidence of ammonium toxicity symptoms. Using A. thaliana frostbite1 as a model plant that overcomes growth repression on ammonium, we have shown that its resistance to enhanced MG levels is based on increased GLXI activity and tolerance to elevated MG-derived advanced glycation end-product (MAGE) levels. Furthermore, our results show that glyoxalase pathway activity strongly affects cellular antioxidative systems. Under stress conditions, the disruption of the MG detoxification pathway limits the functioning of antioxidant defense. However, under optimal growth conditions, a defect in the MG detoxification route results in the activation of antioxidative systems.
Topics: Arabidopsis; Lactoylglutathione Lyase; Pyruvaldehyde; Ammonium Compounds; Arabidopsis Proteins; Plants; Antioxidants
PubMed: 36242617
DOI: 10.1007/s00299-022-02931-5 -
Journal of Physiology and Pharmacology... Jun 2014Chitosan is biocompatible polymer obtained from chitin, the building component of the crustacean shells. In this paper we make an attempt to review the current state of... (Review)
Review
Chitosan is biocompatible polymer obtained from chitin, the building component of the crustacean shells. In this paper we make an attempt to review the current state of knowledge on some biological effects of chitosan in comparison with those of cationically modified chitosan, N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride (HTCC) that was recently synthetized by us by covalent attachment of glycidyltrimethylammonium chloride (GTMAC). Biological effects of HTCC and non-modified polymer are very similar. However, HTCC shows some unique beneficial properties which have not been found in its non-modified counterpart. One such example is that HTCC has the ability to bind heparin at physiological pH. HTCC having the degree of substitution almost 63.6% is easily absorbed within 1 hour after oral administration as found in C57BL/6j mice using FITC-labeled polymer. HTCC is distributed to lung, heart, and kidneys. HTCC stimulates and enhances blood platelet aggregation and decreases erythrocyte deformability (RBC). Moreover, HTCC seems to decrease both plasma total cholesterol level and LDL-cholesterol level in apoE-knockout mice fed with a diet containing HTCC. HTCC possibly down-regulates the HMG-CoAR mRNA level after 24 hour incubation with HepG2 cells in vitro.
Topics: Animals; Chitosan; Humans; Quaternary Ammonium Compounds
PubMed: 24930505
DOI: No ID Found -
Open Biology Jul 2022Transporter proteins are a vital interface between cells and their environment. In nutrient-limited environments, microbes with transporters that are effective at...
Transporter proteins are a vital interface between cells and their environment. In nutrient-limited environments, microbes with transporters that are effective at bringing substrates into their cells will gain a competitive advantage over variants with reduced transport function. Microbial ammonium transporters (Amt) bring ammonium into the cytoplasm from the surrounding periplasm space, but diagnosing Amt adaptations to low nutrient environments solely from sequence data has been elusive. Here, we report altered Amt sequence amino acid distribution from deep marine samples compared to variants sampled from shallow water in two important microbial lineages of the marine water column community-Marine Group I Archaea (Thermoproteota) and the uncultivated gammaproteobacterial lineage SAR86. This pattern indicates an evolutionary pressure towards an increasing dipole in Amt for these clades in deep ocean environments and is predicted to generate stronger electric fields facilitating ammonium acquisition. This pattern of increasing dipole charge with depth was not observed in lineages capable of accessing alternative nitrogen sources, including the abundant alphaproteobacterial clade SAR11. We speculate that competition for ammonium in the deep ocean drives transporter sequence evolution. The low concentration of ammonium in the deep ocean is therefore likely due to rapid uptake by Amts concurrent with decreasing nutrient flux.
Topics: Ammonium Compounds; Archaea; Membrane Transport Proteins; Nutrients; Water
PubMed: 35857930
DOI: 10.1098/rsob.220041 -
Scientific Reports Jun 2020Sigma-1 and sigma-2 receptors are emerging therapeutic targets. We have identified that simple ammonium salts bind to these receptors and are effective in vivo....
Sigma-1 and sigma-2 receptors are emerging therapeutic targets. We have identified that simple ammonium salts bind to these receptors and are effective in vivo. Radioligand binding assays were used to obtain structure-activity relationships of these salts. MTS assays were performed to determine their effect on growth in MCF7 and MDA-MB-486 cells. Anticancer properties were tested in NMRI mice transplanted with a fragment of mouse adenocarcinoma (MAC13). Antidepressant activity was tested using the forced-swim test and tail suspension tests. Dipentylammonium (K 43 nM), tripentylammonium (K 15 nM) and trihexylammonium (K 9 nM) showed high affinity for the sigma-1 receptor. Dioctanoylammonium had the highest affinity (K 0.05 nM); this also showed the highest affinity for sigma-2 receptors (K 13 nM). Dipentylammonium was found to have antidepressant activity in vivo. Branched-chain ammonium salts showed lower affinity. Bis(2-ethylhexyl)ammonium (K 29 µM), triisopentylammonium (K 196 µM) and dioctanoylammonium showed a low Hill slope, and fitted a 2-site binding model for the sigma-1 receptor. We propose this two-site binding can be used to biochemically define a sigma-1 receptor antagonist. Bis(2-ethylhexyl)ammonium and triisopentylammonium were able to inhibit the growth of tumours in vivo. Cheap, simple ammonium salts act as sigma-1 receptor agonists and antagonists in vivo and require further investigation.
Topics: Ammonium Compounds; Antidepressive Agents; Antineoplastic Agents; Calcium; Cell Proliferation; Depression; Humans; MCF-7 Cells; Molecular Targeted Therapy; Neoplasms; Receptors, sigma; Salts; Sigma-1 Receptor
PubMed: 32514120
DOI: 10.1038/s41598-020-65849-6 -
ChemMedChem Apr 2020Thirty-six biscationic quaternary ammonium compounds were efficiently synthesized in one step to examine the effect of molecular geometry of two-carbon linkers on...
Thirty-six biscationic quaternary ammonium compounds were efficiently synthesized in one step to examine the effect of molecular geometry of two-carbon linkers on antimicrobial activity. The synthesized compounds showed strong antimicrobial activity against a panel of both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). While the linker geometry showed only a modest correlation with antimicrobial activity, several of the synthesized bisQACs are promising potential antiseptics due to good antimicrobial activity (MIC≤2 μM) and their higher therapeutic indices compared to previously reported QACs.
Topics: Anti-Bacterial Agents; Dose-Response Relationship, Drug; Gram-Negative Bacteria; Gram-Positive Bacteria; Microbial Sensitivity Tests; Molecular Structure; Quaternary Ammonium Compounds; Surface-Active Agents
PubMed: 32022457
DOI: 10.1002/cmdc.201900662 -
The Biochemical Journal Oct 1996Cation-pi bonds and amino-aromatic interactions are known to be important contributors to protein architecture and stability, and their role in ligand-protein... (Review)
Review
Cation-pi bonds and amino-aromatic interactions are known to be important contributors to protein architecture and stability, and their role in ligand-protein interactions has also been reported. Many biologically active amines contain substituted ammonium moieties, and cation-pi bonding and amino-aromatic interactions often enable these molecules to associate with proteins. The role of organic cation-pi bonding and amino-aromatic interactions in the recognition of small-molecule amines and peptides by proteins is an important topic for those involved in structure-based drug design, and although the number of structures determined for proteins displaying these interactions is small, general features are beginning to emerge. This review explores the role of cation-pi bonding and amino-aromatic interactions in the biological molecular recognition of amine ligands. Perspectives on the design of ammonium-ligand-binding sites are also discussed.
Topics: Amino Acids; Animals; Cations; Drug Design; Humans; Ligands; Protein Binding; Quaternary Ammonium Compounds
PubMed: 8870640
DOI: 10.1042/bj3190001