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Bioresource Technology Sep 2022The low tolerance of marine microalgae to ammonium and hyposalinity limits their use in urban wastewater (UWW) treatments. In this study, using the marine microalga...
The low tolerance of marine microalgae to ammonium and hyposalinity limits their use in urban wastewater (UWW) treatments. In this study, using the marine microalga Amphidinium carterae, it is demonstrated for the first time that this obstacle can be overcome by introducing a zeolite-based adsorption step to obtain a tolerable UWW stream. The maximum ammonium adsorption capacities measured in the natural zeolite used are among the highest reported. The microalga grows satisfactorily in mixtures of zeolite-treated UWW and seawater at a wide range of proportions, both with and without adjusting the salinity, as long as the ammonium concentration is below the threshold tolerated by the microalgae (6.3 mg L). A proof of concept performed in 10-L bubble column photobioreactors with different culture strategies, including medium recycling, showed an enhanced biomass yield relative to a control with no UWW. No noticeable effect was observed on the production of specialty metabolites.
Topics: Adsorption; Ammonium Compounds; Biomass; Microalgae; Photobioreactors; Wastewater; Zeolites
PubMed: 35724909
DOI: 10.1016/j.biortech.2022.127490 -
ELife Jul 2020The transport of charged molecules across biological membranes faces the dual problem of accommodating charges in a highly hydrophobic environment while maintaining...
The transport of charged molecules across biological membranes faces the dual problem of accommodating charges in a highly hydrophobic environment while maintaining selective substrate translocation. This has been the subject of a particular controversy for the exchange of ammonium across cellular membranes, an essential process in all domains of life. Ammonium transport is mediated by the ubiquitous Amt/Mep/Rh transporters that includes the human Rhesus factors. Here, using a combination of electrophysiology, yeast functional complementation and extended molecular dynamics simulations, we reveal a unique two-lane pathway for electrogenic NH transport in two archetypal members of the family, the transporters AmtB from and Rh50 from . The pathway underpins a mechanism by which charged H and neutral NH are carried separately across the membrane after NH deprotonation. This mechanism defines a new principle of achieving transport selectivity against competing ions in a biological transport process.
Topics: Ammonia; Ammonium Compounds; Escherichia coli; Ion Transport; Nitrosomonas europaea
PubMed: 32662768
DOI: 10.7554/eLife.57183 -
Journal of Applied Microbiology Dec 2014This study gives a systematic profile of ammonium overconsumption in anammox consortia beyond the stoichiometry ratio, with aim to reveal another ammonium removal...
AIMS
This study gives a systematic profile of ammonium overconsumption in anammox consortia beyond the stoichiometry ratio, with aim to reveal another ammonium removal process by oxidants OH· without nitrite under anaerobic conditions.
METHODS AND RESULTS
Percoll centrifugation, flow cytometry, cloning and chemical analysis demonstrated that this ammonium removal was related to low Planctomycetes and high biomass decay. Armatimonadetes, Acidobacteria, Verrucomicrobia and Nitrosomonas initially existed in the consortia with the overconsumption of ammonium, and their levels then declined with decreasing overconsumption. The inevitable release of oxidants, such as OH, during bacterial inhibition or decay was found to be a potential source of electron acceptors capable of oxidizing ammonium.
CONCLUSIONS
Anaerobic ammonium removal without nitrite could occur in anammox consortia. However, it was unsteady and was not sustained over a long period. Under suitable conditions, anammox bacteria competed with others and became the dominant micro-organism responsible for the simultaneous removal of ammonium and nitrite.
SIGNIFICANCE AND IMPACTS OF THE STUDY
This investigation will have importance to better understand the anammox process operation. The overconsumption of ammonium could be used as an indicator for fluctuations in anammox cultivation.
Topics: Ammonium Compounds; Anaerobiosis; Bacteria; Microbial Consortia; Nitrites; Oxidation-Reduction
PubMed: 25210947
DOI: 10.1111/jam.12649 -
Cells Nov 2022Plants absorb nitrogen from the soil using ammonium transporters (AMTs). Plants can precisely regulate AMT1;3 levels using sophisticated regulatory systems, ensuring...
Plants absorb nitrogen from the soil using ammonium transporters (AMTs). Plants can precisely regulate AMT1;3 levels using sophisticated regulatory systems, ensuring adequate nitrogen uptake without hazardous ammonium production. Here, we demonstrated that ubiquitylation can contribute to AMT1;3 degradation under high ammonium stress. Using the ubiquitin site mutant AMT1;3-EGFP, we demonstrated that the loss of ubiquitination affects the dynamic characteristics of AMT1;3 proteins on the plasma membrane and markedly inhibits the endocytosis of AMT1;3 proteins under high ammonium stress. AMT1;3-EGFP plants also showed inhibition of protein degradation that targets the vesicular pathway after being exposed to high levels of ammonium. Our findings showed that the dynamic properties, endocytosis, and vesicle trafficking pathways of AMT1;3 proteins are altered in AMT1;3-EGFP under high ammonium conditions.
Topics: Ammonium Compounds; Arabidopsis; Cation Transport Proteins; Plant Proteins; Nitrogen; Ubiquitination
PubMed: 36429077
DOI: 10.3390/cells11223651 -
Journal of the American Chemical Society Jul 2021Aerobic alcohol oxidations catalyzed by transition metal salts and aminoxyls are prominent examples of cooperative catalysis. Cu/aminoxyl catalysts have been studied...
Aerobic alcohol oxidations catalyzed by transition metal salts and aminoxyls are prominent examples of cooperative catalysis. Cu/aminoxyl catalysts have been studied previously and feature "integrated cooperativity", in which Cu and the aminoxyl participate together to mediate alcohol oxidation. Here we investigate a complementary Fe/aminoxyl catalyst system and provide evidence for "serial cooperativity", involving a redox cascade wherein the alcohol is oxidized by an in situ-generated oxoammonium species, which is directly detected in the catalytic reaction mixture by cyclic step chronoamperometry. The mechanistic difference between the Cu- and Fe-based catalysts arises from the use iron(III) nitrate, which initiates a NO-based redox cycle for oxidation of aminoxyl/hydroxylamine to oxoammonium. The different mechanisms for the Cu- and Fe-based catalyst systems are manifested in different alcohol oxidation chemoselectivity and functional group compatibility.
Topics: Alcohols; Catalysis; Cyclic N-Oxides; Ferric Compounds; Molecular Structure; Nitrates; Oxidation-Reduction; Quaternary Ammonium Compounds
PubMed: 34232661
DOI: 10.1021/jacs.1c05224 -
FEMS Microbiology Ecology Oct 2018Reduced nitrogen species are key nutrients for biological productivity in the oceans. Ammonium is often present in low and growth-limiting concentrations, albeit peaks...
Reduced nitrogen species are key nutrients for biological productivity in the oceans. Ammonium is often present in low and growth-limiting concentrations, albeit peaks occur during collapse of algal blooms or via input from deep sea upwelling and riverine inflow. Autotrophic phytoplankton exploit ammonium peaks by storing nitrogen intracellularly. In contrast, the strategy of heterotrophic bacterioplankton to acquire ammonium is less well understood. This study revealed the marine bacterium Phaeobacter inhibens DSM 17395, a Roseobacter group member, to have already depleted the external ammonium when only ∼⅓ of the ultimately attained biomass is formed. This was paralleled by a three-fold increase in cellular nitrogen levels and rapid buildup of various nitrogen-containing intracellular metabolites (and enzymes for their biosynthesis) and biopolymers (DNA, RNA and proteins). Moreover, nitrogen-rich cells secreted potential RTX proteins and the antibiotic tropodithietic acid, perhaps to competitively secure pulses of external ammonium and to protect themselves from predation. This complex response may ensure growing cells and their descendants exclusive provision with internal nitrogen stocks. This nutritional strategy appears prevalent also in other roseobacters from distant geographical provenances and could provide a new perspective on the distribution of reduced nitrogen in marine environments, i.e. temporary accumulation in bacterioplankton cells.
Topics: Ammonium Compounds; Anti-Bacterial Agents; Bacterial Proteins; Biomass; Heterotrophic Processes; Nitrogen; Plankton; Roseobacter; Seawater; Tropolone
PubMed: 30124819
DOI: 10.1093/femsec/fiy154 -
International Journal of Molecular... Feb 2024Organic ammonium and phosphonium salts exert excellent antimicrobial effects by interacting lethally with bacterial membranes. Particularly, quaternary ammonium lipids...
Organic ammonium and phosphonium salts exert excellent antimicrobial effects by interacting lethally with bacterial membranes. Particularly, quaternary ammonium lipids have demonstrated efficiency both as gene vectors and antibacterial agents. Here, aiming at finding new antibacterial devices belonging to both classes, we prepared a water-soluble quaternary ammonium lipid () and a phosphonium salt () by designing a synthetic path where would be an intermediate to achieve . All synthesized compounds were characterized by Fourier-transform infrared spectroscopy and Nuclear Magnetic Resonance. Additionally, potentiometric titrations of NH groups and were performed to further confirm their structure by determining their experimental molecular weight. The antibacterial activities of and were assessed first against a selection of multi-drug-resistant clinical isolates of both Gram-positive and Gram-negative species, observing remarkable antibacterial activity of both compounds against Gram-positive isolates of and genus. Further investigations on a wider variety of strains of these species confirmed the remarkable antibacterial effects of and (MICs = 4-16 and 4-64 µg/mL, respectively), while 24 h-time-killing experiments carried out with on different isolates evidenced a bacteriostatic behavior. Moreover, both compounds and , at the lower MIC concentration, did not show significant cytotoxic effects when exposed to HepG2 human hepatic cell lines, paving the way for their potential clinical application.
Topics: Humans; Ammonium Compounds; Staphylococcus aureus; Quaternary Ammonium Compounds; Anti-Bacterial Agents; Gram-Positive Bacteria; Bacteria; Sodium Chloride; Sodium Chloride, Dietary; Lipids; Microbial Sensitivity Tests
PubMed: 38474008
DOI: 10.3390/ijms25052761 -
Molecules (Basel, Switzerland) Apr 2010Two novel organic-inorganic compounds based on tetrahexylammonium (THA) and tetraheptylammonium (THPA) ions and the Preyssler anion, [NaP5W30O110]14-, were synthesized...
Synthesis and characterization of two novel organic-inorganic compounds based on tetrahexyl and tetraheptyl ammonium ions and the Preyssler anion and their catalytic activities in the synthesis of 4-aminopyrazolo[3,4-d]- pyrimidines.
Two novel organic-inorganic compounds based on tetrahexylammonium (THA) and tetraheptylammonium (THPA) ions and the Preyssler anion, [NaP5W30O110]14-, were synthesized and formulated as (THA)7.7H6.3 [NaP5W30O110] (A) and (THPA)7.5 H6.5[NaP5W30O110] (B). The synthesized compounds were characterized by IR, UV, and TGA and used for the catalytic synthesis of 4-aminopyrazolo[3,4,-d]pyrimidine derivatives 2a-2d. Our findings showed efficient catalytic activities for A and B.
Topics: Adenine; Catalysis; Conductometry; Potentiometry; Pyrimidines; Quaternary Ammonium Compounds; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet; Thermogravimetry; Tungsten Compounds
PubMed: 20428060
DOI: 10.3390/molecules15042509 -
Scientific Reports Jul 2023The mechanisms governing chemotaxis in Chlamydomonas reinhardtii are largely unknown compared to those regulating phototaxis despite equal importance on the migratory...
The mechanisms governing chemotaxis in Chlamydomonas reinhardtii are largely unknown compared to those regulating phototaxis despite equal importance on the migratory response in the ciliated microalga. To study chemotaxis, we made a simple modification to a conventional Petri dish assay. Using the assay, a novel mechanism governing Chlamydomonas ammonium chemotaxis was revealed. First, we found that light exposure enhances the chemotactic response of wild-type Chlamydomonas strains, yet phototaxis-incompetent mutant strains, eye3-2 and ptx1, exhibit normal chemotaxis. This suggests that Chlamydomonas transduces the light signal pathway in chemotaxis differently from that in phototaxis. Second, we found that Chlamydomonas collectively migrate during chemotaxis but not phototaxis. Collective migration during chemotaxis is not clearly observed when the assay is conducted in the dark. Third, the Chlamydomonas strain CC-124 carrying agg1, the AGGREGATE1 gene (AGG1) null mutation, exhibited a more robust collective migratory response than strains carrying the wild-type AGG1 gene. The expression of a recombinant AGG1 protein in the CC-124 strain suppressed this collective migration during chemotaxis. Altogether, these findings suggest a unique mechanism; ammonium chemotaxis in Chlamydomonas is mainly driven by collective cell migration. Furthermore, it is proposed that collective migration is enhanced by light and suppressed by the AGG1 protein.
Topics: Chlamydomonas reinhardtii; Chemotaxis; Ammonium Compounds; Chlamydomonas; Cell Movement; Light
PubMed: 37402785
DOI: 10.1038/s41598-023-36818-6 -
The Journal of Organic Chemistry May 2024Anions have a profound effect on the properties of soluble proteins. Such Hofmeister effects have implications in biologics stability, protein aggregation,...
Anions have a profound effect on the properties of soluble proteins. Such Hofmeister effects have implications in biologics stability, protein aggregation, amyloidogenesis, and crystallization. However, the interplay between the important noncovalent interactions (NCIs) responsible for Hofmeister effects is poorly understood. To contribute to improving this state of affairs, we report on the NCIs between anions and ammonium and guanidinium hosts and , and the consequences of these. Specifically, we investigate the properties of cavitands designed to mimic two prime residues for anion-protein NCIs─lysines and arginines─and the solubility consequences of complex formation. Thus, we report NMR and ITC affinity studies, X-ray analysis, MD simulations, and anion-induced critical precipitation concentrations. Our findings emphasize the multitude of NCIs that guanidiniums can form and how this repertoire qualitatively surpasses that of ammoniums. Additionally, our studies demonstrate the ease by which anions can dispense with a fraction of their hydration-shell waters, rearrange those that remain, and form direct NCIs with the hosts. This raises many questions concerning how solvent shell plasticity varies as a function of anion, how the energetics of this impact the different NCIs between anions and ammoniums/guanidiniums, and how this affects the aggregation of solutes at high anion concentrations.
Topics: Guanidine; Anions; Arginine; Ammonium Compounds; Lysine; Molecular Dynamics Simulation
PubMed: 38662908
DOI: 10.1021/acs.joc.4c00242