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Environmental Research Sep 2023Perchlorate and chlorate are endocrine disruptors considered emerging contaminants (ECs). Both oxyanions are commonly associated with anthropogenic contamination from...
Perchlorate and chlorate are endocrine disruptors considered emerging contaminants (ECs). Both oxyanions are commonly associated with anthropogenic contamination from fertilizers, pesticides, explosives, and disinfection byproducts. However, the soils of the Atacama Desert are the most extensive natural reservoirs of perchlorate in the world, compromising drinking water sources in northern Chile. Field campaigns were carried (2014-2018) to assess the presence of these ECs in the water supply networks of twelve Chilean cities. Additionally, the occurrence of perchlorate, chlorate and other anions typically observed in drinking water matrices of the Atacama Desert (i.e., nitrate, chloride, sulfate) was evaluated using a Spearman correlation analysis to determine predictors for perchlorate and chlorate. High concentrations of perchlorate (up to 114.48 μg L) and chlorate (up to 9650 μg L) were found in three northern cities. Spatial heterogeneities were observed in the physicochemical properties and anion concentrations of the water supply network. Spearman correlation analysis indicated that nitrate, chloride, and sulfate were not useful predictors for the presence of perchlorate and chlorate in drinking water in Chile. Hence, this study highlights the need to establish systematic monitoring, regulation, and treatment for these EC of drinking water sources in northern Chilean cities for public health protection.
Topics: Drinking Water; Chlorates; Chile; Nitrates; Perchlorates; Cities; Chlorides; Water Pollutants, Chemical
PubMed: 37343761
DOI: 10.1016/j.envres.2023.116450 -
Chemistry (Weinheim An Der Bergstrasse,... Aug 2023Single molecules that co-transport cations as well as anions across lipid membranes are few despite their high biological utility. The elegant yet simple lipidomimmetic...
Single molecules that co-transport cations as well as anions across lipid membranes are few despite their high biological utility. The elegant yet simple lipidomimmetic peptide design herein enables efficient HCl transport without the use of any external additives for proton transport. The carboxylic acids in the dipeptide scaffold provide a handle to append two long hydrophobic tails and also provide a polar hydrophilic carboxylate group. The peptide central unit also provides NH sites for anion binding. Protonation of the carboxylate group coupled with the weak halide binding of the terminal NH group results in HCl transport with transport rates of H >Cl . The lipid-like structure also facilitates seamless membrane integration and flipping of the molecule. The biocompatibility, design simplicity, and potential pH regulation of these molecules open up several avenues for their therapeutic use.
Topics: Ion Transport; Anions; Peptides; Lipids; Biological Transport
PubMed: 37218621
DOI: 10.1002/chem.202301020 -
Molecules (Basel, Switzerland) Oct 2023The formulation of magnetic ionic liquids (MILs) or organic salts based on lanthanides as anions has been explored. In this work, a set of choline-family-based salts,...
The formulation of magnetic ionic liquids (MILs) or organic salts based on lanthanides as anions has been explored. In this work, a set of choline-family-based salts, and two other, different cation families, were combined with Gadolinium(III) and Terbium(III) anions. Synthetic methodologies were previously optimized, and all organic salts were obtained as solids with melting temperatures higher than 100 °C. The magnetic moments obtained for the Gd(III) salts were, as expected, smaller than those obtained for the Tb(III)-based compounds. The values for Gd(III) and Tb(III) magnetic salts are in the range of 6.55-7.30 MB and 8.22-9.34 MB, respectively. It is important to note a correlation between the magnetic moments obtained for lanthanides, and the structural features of the cation. The cytotoxicity of lanthanide-based salts was also evaluated using 3T3, 293T, Caco2, and HepG2 cells, and it was revealed that most of the prepared compounds are not toxic.
Topics: Humans; Lanthanoid Series Elements; Salts; Caco-2 Cells; Anions; Cations
PubMed: 37894633
DOI: 10.3390/molecules28207152 -
Macromolecular Bioscience Aug 2023Depending on their architectural and chemical design, microgels can selectively take up and release small molecules by changing the environmental properties, or capture...
Depending on their architectural and chemical design, microgels can selectively take up and release small molecules by changing the environmental properties, or capture and protect their cargo from the surrounding conditions. These outstanding properties make them promising candidates for use in biomedical applications as delivery or carrier systems. In this study, hollow anionic p(N-isopropylacrylamid-e-co-itaconic acid) microgels are synthesized and analyzed regarding their size, charge, and charge distribution. Furthermore, interactions between these microgels and the model protein cytochrome c are investigated as a function of pH. In this system, pH serves as a switch for the electrostatic interactions to alternate between no interaction, attraction, and repulsion. UV-vis spectroscopy is used to quantitatively study the encapsulation of cytochrome c and possible leakage. Additionally, fluorescence-lifetime images unravel the spatial distribution of the protein within the hollow microgels as a function of pH. These analyses show that cytochrome c mainly remains entrapped in the microgel, with pH controlling the localization of the protein - either in the microgel's cavity or in its network. This significantly differentiates these hollow microgels from microgels with similar chemical composition but without a solvent filled cavity.
Topics: Capsules; Hydrogen-Ion Concentration; Microgels; Nanostructures; Cytochromes c; Anions
PubMed: 36605024
DOI: 10.1002/mabi.202200456 -
Journal of Visualized Experiments : JoVE Aug 2023A protocol for rapid, microwave-assisted hydrothermal synthesis of nickel hydroxide nanosheets under mildly acidic conditions is presented, and the effect of reaction...
A protocol for rapid, microwave-assisted hydrothermal synthesis of nickel hydroxide nanosheets under mildly acidic conditions is presented, and the effect of reaction temperature and time on the material's structure is examined. All reaction conditions studied result in aggregates of layered α-Ni(OH)2 nanosheets. The reaction temperature and time strongly influence the structure of the material and product yield. Synthesizing α-Ni(OH)2 at higher temperatures increases the reaction yield, lowers the interlayer spacing, increases crystalline domain size, shifts the frequencies of interlayer anion vibrational modes, and lowers the pore diameter. Longer reaction times increase reaction yields and result in similar crystalline domain sizes. Monitoring the reaction pressure in situ shows that higher pressures are obtained at higher reaction temperatures. This microwave-assisted synthesis route provides a rapid, high-throughput, scalable process that can be applied to the synthesis and production of a variety of transition metal hydroxides used for numerous energy storage, catalysis, sensor, and other applications.
Topics: Nickel; Microwaves; Hydroxides; Catalysis
PubMed: 37607084
DOI: 10.3791/65412 -
Proceedings of the National Academy of... Nov 2023The elemental composition of coral skeletons provides important information for palaeoceanographic reconstructions and coral biomineralization. Partition of anions and...
The elemental composition of coral skeletons provides important information for palaeoceanographic reconstructions and coral biomineralization. Partition of anions and their stable isotopes in coral skeleton enables the reconstruction of past seawater carbonate chemistry, paleo-CO, and past climates. Here, we investigated the partition of B, S, As, Br, I, and Mo into the skeletons of two corals, and , as a function of calcium and carbonate concentrations. Anion-to-calcium ratio in the corals (An/Ca) were correlated with the equivalent ratios in the culturing seawater (An/CO). Negative intercepts of these relationships suggest a higher CO concentration in the coral extracellular calcifying fluid (ECF) relative to seawater, from which the skeleton precipitates. The enrichment factor of CO at the ECF was 2.5 for and 1.9 for , consistent with their relative calcification rates. The CO concentrations thus calculated are similar to those proposed by previous studies based on B/Ca coupled with δB, as well as by direct measurements using microsensors and fluorescent dyes. Rayleigh fractionation modeling demonstrates a uniform Ca utilization at various Ca concentrations, providing further evidence that coral calcification occurs directly from a semiclosed seawater reservoir as reported previously. The partition coefficients reported in this study for B, S, As, Br, I, and Mo open up wide possibilities for past ocean chemistry reconstructions based on Br having long residence time (~160 Ma) in the ocean. Other elements like S, Mo, B, as well as CO may also be calculated based on these elements in fossil coral.
Topics: Animals; Anthozoa; Calcium; Biomineralization; Calcium Carbonate; Hydrogen-Ion Concentration; Carbonates; Seawater; Calcification, Physiologic; Calcinosis; Coral Reefs
PubMed: 37917794
DOI: 10.1073/pnas.2306627120 -
Talanta Dec 2023Excessive levels of cyanide (CN) and hypochlorite (ClO) anions are the significant threats to the human health and the environment. Thus, great efforts have been to...
Excessive levels of cyanide (CN) and hypochlorite (ClO) anions are the significant threats to the human health and the environment. Thus, great efforts have been to design and synthesize molecular sensors for the simple, instantaneous and efficient detecting environmentally and biologically important anions. Currently, developing a single molecular sensor for multi-analyte sensing is still a challenging task. In our present work, we developed a new molecular sensor (3TM) based on oligothiophene and Meldrum's acid units for detecting cyanide and hypochlorite anions in biological, environmental and food samples. The detecting ability of 3TM has been examined to various testing substances containing amino acids, reactive oxygen species, cations and anions, showing its high selectivity, excellent sensitivity, short response time (ClO: 30 s, CN: 100 s), and broad pH working range (4-10). The detection limits were calculated as 4.2 nM for ClO in DMSO/HO (1/8, v/v) solution and 6.5 nM for CN in DMSO/HO (1/99, v/v) solution. Sensor 3TM displayed sharp turn-on fluorescence increasement (555 nm, 435 nm) and sensitive fluorescence color changes caused by CN/ClO, which is ascribed to the nucleophilic addition and oxidation of ethylenic linkage by cyanide and hypochlorite, respectively. Moreover, sensor 3TM was applied for hypochlorite and cyanide detecting in real-world water, food samples and bio-imaging in live cells and zebrafish. To our knowledge, the developed 3TM sensor is the seventh single-molecular sensor for simultaneous and discriminative detecting hypochlorite and cyanide in food, biological and aqueous environments using two distinct sensing modes.
Topics: Animals; Humans; Cyanides; Zebrafish; Hypochlorous Acid; Dimethyl Sulfoxide; Fluorescent Dyes; Anions; Water
PubMed: 37418961
DOI: 10.1016/j.talanta.2023.124910 -
Ecotoxicology and Environmental Safety Sep 2023Studtite and meta-studtite are the only two uranyl peroxides found in nature. Sparsely soluble studtite has been found in natural uranium deposits, on the surface of...
Studtite and meta-studtite are the only two uranyl peroxides found in nature. Sparsely soluble studtite has been found in natural uranium deposits, on the surface of spent nuclear fuel in contact with water and on core material from major nuclear accidents such as Chernobyl. The formation of studtite on the surface of nuclear fuel can have an impact on the release of radionuclides to the biosphere. In this work, we have experimentally studied the formation of studtite as function of HCO concentration and pH. The results show that studtite can form at pH ≤ 10 in solutions without added HCO. At pH ≤ 7, the precipitate was found to be mainly studtite, while at 8 ≤ pH ≤ 9.8, a mixture of studtite and meta-schoepite was found. Studtite formation from UO and HO was observed at [HCO] ≤ 2 mM and studtite was only found to dissolve at [HCO] > 2 mM.
Topics: Bicarbonates; Hydrogen Peroxide; Uranium Compounds; Peroxides; Water
PubMed: 37494736
DOI: 10.1016/j.ecoenv.2023.115297 -
Biochimica Et Biophysica Acta. Proteins... Nov 2023Activity-based protein profiling has facilitated the study of the activity of enzymes in proteomes, inhibitor development, and identification of enzymes that share...
Activity-based protein profiling has facilitated the study of the activity of enzymes in proteomes, inhibitor development, and identification of enzymes that share mechanistic and active-site architectural features. Since methyl acyl phosphate monoesters act as electrostatically selective anionic electrophiles for the covalent modification of nucleophiles that reside adjacent to cationic sites in proteins, we synthesized methyl hex-5-ynoyl phosphate (MHP) to broadly target such protein architectures. After treating the soluble proteome of Paucimonas lemoignei with MHP, biotinylating the resulting acylated proteins using click chemistry, enriching the protein adducts using streptavidin, and analyzing the proteins by LC-MS/MS, a set of 240 enzymes and 132 non-enzyme proteins were identified for a wide spectrum of biological processes and from all 7 enzyme classes. Among those enzymes identified, β-hydroxybutyrate dehydrogenase (PlHBDH) and CTP synthase (E. coli orthologue, EcCTPS) were purified as recombinant enzymes and their rates of inactivation and sites of modification by MHP and methyl acetyl phosphate (MAP) were characterized. MHP reacted more slowly with these proteins than MAP but exhibited greater specificity, despite its lack of multiple binding determinants. Generally, MAP modified more surface residues than MHP. MHP specifically modified Ser 146, Lys 156, and Lys 163 at the active site of PlHBDH. MHP and MAP modified numerous residues of EcCTPS with CTP furnishing the greatest level of protection against MHP- and MAP-dependent modification and inactivation, respectively, followed by ATP and glutamine. Overall, MHP served as an effective probe to identify proteins that are potentially amenable to inhibition by methyl acyl phosphates.
Topics: Chromatography, Liquid; Escherichia coli; Phosphates; Tandem Mass Spectrometry; Proteins
PubMed: 37536394
DOI: 10.1016/j.bbapap.2023.140945 -
Biophysical Journal Jun 2024The light-gated anion channelrhodopsin GtACR1 is an important optogenetic tool for neuronal silencing. Its photochemistry, including its photointermediates, is poorly...
The light-gated anion channelrhodopsin GtACR1 is an important optogenetic tool for neuronal silencing. Its photochemistry, including its photointermediates, is poorly understood. The current mechanistic view presumes BR-like kinetics and assigns the open channel to a blue-absorbing L intermediate. Based on time-resolved absorption and electrophysiological data, we recently proposed a red-absorbing spectral form for the open channel state. Here, we report the results of a comprehensive kinetic analysis of the spectroscopic data combined with channel current information. The time evolutions of the spectral forms derived from the spectroscopic data are inconsistent with the single chain mechanism and are analyzed within the concept of parallel photocycles. The spectral forms partitioned into conductive and nonconductive parallel cycles are assigned to intermediate states. Rejecting reversible connections between conductive and nonconductive channel states leads to kinetic schemes with two independent conductive states corresponding to the fast- and slow-decaying current components. The conductive cycle is discussed in terms of a single cycle and two parallel cycles. The reaction mechanisms and reaction rates for the wild-type protein, the A75E, and the low-conductance D234N and S97E protein variants are derived. The parallel cycles of channelrhodopsin kinetics, its relation to BR photocycle, and the role of the M intermediate in channel closure are discussed.
Topics: Kinetics; Ion Channel Gating; Rhodopsin; Animals; Anions; Light; Models, Biological; Channelrhodopsins
PubMed: 38762755
DOI: 10.1016/j.bpj.2024.05.016