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Environmental Science & Technology Dec 2023Methyl halides play important roles in stratospheric ozone depletion, but their formation mechanisms are not well defined. This study demonstrated that iron-based...
Methyl halides play important roles in stratospheric ozone depletion, but their formation mechanisms are not well defined. This study demonstrated that iron-based photochemistry significantly enhanced alkyl halide production by promoting the reaction of the representative monomer of lignin with halide ions in saline water under solar light irradiation. The methyl chloride (CHCl) emission from the light/Fe(III) process was 2 orders of magnitude higher than dark treatment and in the absence of iron. In addition, bromide and iodide showed better reactivity in the formation of the corresponding methyl bromide (CHBr) and methyl iodide (CHI). Alkyl halides identified from seawater, brackish water, and salt pan water under sunlight irradiation were positively correlated with the Fe(III) concentrations, indicating that iron-based photochemistry is ubiquitous. This work suggested that the photoinduced formation of methyl radical and redox cycling of iron triggered by the Fenton-like reaction are responsible for the enhanced release of alkyl halides. This study represents an abiotic formation pathway of alkyl halides, which accounts for a portion of the unidentified sources of halocarbons in the ocean.
Topics: Iron; Photochemistry; Hydrocarbons, Halogenated; Seawater; Ferric Compounds
PubMed: 38010203
DOI: 10.1021/acs.est.3c05552 -
Biochimica Et Biophysica Acta.... May 2022The calcium-activated chloride channel TMEM16A (ANO1) supports the passive movement of chloride ions across membranes and controls critical cell functions. Here we study...
The calcium-activated chloride channel TMEM16A (ANO1) supports the passive movement of chloride ions across membranes and controls critical cell functions. Here we study the block of wild-type and mutant TMEM16A channels expressed in HEK293 cells by oleic acid, a monounsaturated omega-9 fatty acid beneficial for cardiovascular health. We found that oleic acid irreversibly blocks TMEM16A in a dose- and voltage-dependent manner at low intracellular Ca. We tested whether oleic acid interacted with the TMEM16A pore, varying the permeant anion concentration and mutating pore residues. Lowering the permeating anion concentration in the intracellular side did nothing but the blockade was intensified by increasing the anion concentration in the extracellular side. However, the blockade of the pore mutants E633A and I641A was voltage-independent, and the I641A IC, a mutant with the inner hydrophobic gate in disarray, increased 16-fold. Furthermore, the uncharged methyl-oleate blocked 20-24% of the wild-type and I641A channels regardless of voltage. Our findings suggest that oleic acid inhibits TMEM16A by an allosteric mechanism after the electric field drives oleic acid's charged moiety inside the pore. Block of TMEM16A might be why oleic acid has a beneficial impact on the cardiovascular system.
Topics: Anions; Anoctamin-1; Calcium; Chloride Channels; HEK293 Cells; Humans; Neoplasm Proteins; Oleic Acid
PubMed: 35202806
DOI: 10.1016/j.bbalip.2022.159134 -
Food Science & Nutrition Feb 2021Fruit quality is preserved through cold storage, but climacteric fruits are prone to chilling injury (CI) which limits their shelf life and marketability. Two...
Fruit quality is preserved through cold storage, but climacteric fruits are prone to chilling injury (CI) which limits their shelf life and marketability. Two postharvest treatments, 1 mM methyl jasmonate (MeJA) and 4% (wt/vol) calcium chloride (Ca), were separately used to investigate their influences on chilling injury (CI) incidence and fruit quality in unpacked banana cultivar "Grand Nain" during cold storage and subsequent ripening. Banana fruits were dipped for 2 min in aqueous emulsions containing 1% Tween-80-used here as a surfactant with untreated fruits being used as control. Fruits were stored at 10 ± 2 or optimal 14 ± 2°C temperature and relative humidity 85%-90% for a 20-day cold storage period and then removed from cold storage at 5, 10, 15, and 20 days followed by ripening at 22 ± 2°C. Treatments with MeJA or Ca significantly reduced CI in banana fruit during cold storage and subsequent ripening temperature. Untreated controls exhibited increased CI, weight loss, and decreased hue angle, as well as firmness. In contrast, the aforementioned changes were considerably delayed after treatments with MeJA or Ca. Application of MeJA or Ca also increased total phenolic compound contents and maintenance of total antioxidant activity throughout cold storage and during ripening periods as compared to that of the control. These findings indicate that coating bananas with 1 mM MeJA or 4% (wt/vol) Ca can improve the postharvest quality and shelf life of fruits, and it can ameliorate chilling injury during cold storage and at ripening temperature.
PubMed: 33598176
DOI: 10.1002/fsn3.2058 -
Iranian Journal of Public Health Mar 2024Multiple Myeloma (MM) is a neoplastic hematologic disorder caused by the excessive proliferation of plasma cells and leads to bone lesions, anemia, and kidney failure.... (Review)
Review
Multiple Myeloma (MM) is a neoplastic hematologic disorder caused by the excessive proliferation of plasma cells and leads to bone lesions, anemia, and kidney failure. No definite etiology has been proposed for MM, but several environmental and genetic risk factors have been implicated so far. Exposure to pesticides, benzene, and organic solvents like methyl chloride have been considered a potential risk factor. Asbestos, ionizing radiation, and wood dust exposure have also been associated with MM. As MM is a relatively rare condition, the number of studies is insufficient, and in many studies, only a few study participants recall exposure to any agents. Therefore, establishing a definite risk factor is cumbersome and further studies with large study samples are needed. By recognizing these occupational risk factors, clinicians can encourage employees to reduce their exposure as more as possible and implement precautionary measures. In this review, we highlighted the current research on the potential association between occupational exposures and MM. Because of these studies, new regulations with the goal of occupational exposure reduction are anticipated in the future.
PubMed: 38919290
DOI: 10.18502/ijph.v53i3.15137 -
ACS Omega Sep 2023Methylene blue (MB) dye or methyl thioninium chloride is one of the hazardous cationic dyes that are discharged into the textile effluent causing a highly negative...
Methylene blue (MB) dye or methyl thioninium chloride is one of the hazardous cationic dyes that are discharged into the textile effluent causing a highly negative environmental impact. The present work targets the investigation of the adsorption performance of some chitosan-modified products toward the MB dye from simulated solutions. The claimed chitosan derivatives were prepared, characterized, and applied for the removal of lead and copper cations from an aqueous medium in a previous work. These include: ,-carboxymethyl chitosan (,-CM/Cs), chitosan grafted with glutaraldehyde (Cs/GA), chitosan cross-linked with GA/epichlorohydrin (Cs/GA/ECH), and chitosan cross-linked with glutaraldehyde/methylene bis(acrylamide) (Cs/GA/MBA). The modified chitosan derivatives in this study displayed outstanding mechanical qualities, exceptional reusability, and a significant amount of adsorption capacity. The ability of prepared Cs derivatives to eradicate MB was as follows: ,-CM/Cs (95.1 mg/g) < Cs/GA (120.1 mg/g) < Cs/GA/ECH (220.1 mg/g) < Cs/GA/MBA (270.0 mg/g). The swelling performance of the prepared sorbents was verified under different experimental conditions, and the data revealed that the maximum swelling was attained at pH = 9, temperature 55 °C, and after 24 h. The produced Cs derivatives showed exceptional reusability by maintaining higher adsorption effectiveness throughout five cycles. The MB dye was adsorbed onto the modified derivatives according to pseudo-second-order kinetics and the Langmuir model. Moreover, the adsorption process was monitored via atomic force microscopy to verify the differences between the dye-free and dye-loaded adsorbents.
PubMed: 37744862
DOI: 10.1021/acsomega.3c03735 -
Acta Crystallographica. Section E,... Sep 2023In the hydrated title salt, CHNS ·Cl·HO, the asymmetric unit comprises one 2-amino-5-{(1)-1-[(carbamo-thioyl-amino)-imino]-eth-yl}-4-methyl-1,3-thia-zol-3-ium cation,...
In the hydrated title salt, CHNS ·Cl·HO, the asymmetric unit comprises one 2-amino-5-{(1)-1-[(carbamo-thioyl-amino)-imino]-eth-yl}-4-methyl-1,3-thia-zol-3-ium cation, one chloride anion and one water mol-ecule of crystallization. The cation is nearly flat (r.m.s. deviation of non-H atoms is 0.0814 Å), with the largest deviation of 0.1484 (14) Å observed for one of the methyl C atoms. In the crystal, the cations are linked by O-H⋯Cl, N-H⋯Cl, N-H⋯O, N-H⋯S and C-H⋯S hydrogen bonds, forming a tri-periodic network. The most important contributions to the crystal packing are from H⋯H (35.4%), S⋯H/H⋯S (24.4%), N⋯H/H⋯N (8.7%), Cl⋯H/H⋯Cl (8.2%) and C⋯H/H⋯C (7.7%) inter-actions.
PubMed: 37693676
DOI: 10.1107/S2056989023007090 -
Plant Physiology and Biochemistry : PPB Jan 2023In this study, the effects of methyl jasmonate (MeJA) and sodium chloride (NaCl) treatments on the resveratrol biosynthesis and physiology of peanuts during germination...
In this study, the effects of methyl jasmonate (MeJA) and sodium chloride (NaCl) treatments on the resveratrol biosynthesis and physiology of peanuts during germination were investigated. The results showed that MeJA (150 μM) and NaCl (150 mM) treatments significantly promoted resveratrol biosynthesis in germinated peanuts. MeJA and NaCl treatments promoted resveratrol accumulation by regulating the activities of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H) and 4-coumarate coenzyme A ligase (4CL) and their gene expression levels in cotyledons and non-cotyledons. In addition, both MeJA and NaCl treatments inhibited peanut sprout growth, as evidenced by shorter sprout length, increased malondialdehyde content, and accumulation of reactive oxygen species in cotyledons and non-cotyledons. Both treatments' germinated peanuts responded to the environmental stimuli by raising the activities of antioxidant enzymes and controlling the levels of their gene' expression. Meanwhile, MeJA and NaCl treatments promoted Ca aggregation in the root tips. Therefore, it can be deduced that Ca may help improve the plant's resistance to adversity. In conclusion, treatment with MeJA (150 μM) or NaCl (150 mM) during germination is an effective way to enrich the resveratrol content of peanuts. Germinated peanuts enhance adaptation to the external environment by promoting resveratrol biosynthesis and enhancing antioxidant systems.
Topics: Resveratrol; Antioxidants; Arachis; Sodium Chloride; Acetates; Cyclopentanes; Oxylipins
PubMed: 36563572
DOI: 10.1016/j.plaphy.2022.12.012 -
Environmental Pollution (Barking, Essex... Jun 2021Plastic particles smaller than 1 μm are considered to be highly dangerous pollutants due to their ability to penetrate living cells. Model experiments on the toxicity...
Plastic particles smaller than 1 μm are considered to be highly dangerous pollutants due to their ability to penetrate living cells. Model experiments on the toxicity of plastics should be correlated with actual concentrations of plastics in natural water. We simulated the natural destruction of polystyrene, polyvinyl chloride, and poly(methyl methacrylate) in experiments on the abrasion of plastics with small stones. The plastics were dyed in mass with a fluorescent dye, which made it possible to distinguish plastic particles from stone fragments. We found that less than 1% of polystyrene and polyvinyl chloride were converted to submicron size particles. In the case of more rigid poly(methyl methacrylate), the fraction of such particles reaches 11%. The concentration of particles with a diameter less than 1 μm in the model experiments was from 0.7 (polystyrene) to 13 mg/L (poly(methyl methacrylate)), and when transferring the obtained data to real reservoirs, these values should be reduced by several orders of magnitude. These data explain the difficulties associated with the search for nanoplastics in natural waters. The toxicity of such particles to hydrobionts in model experiments was detected for concentrations greater than 1 mg/L, which is unrealistic in nature. Detectable and toxic amounts of nano- and submicron plastic particles in living organisms can be expected only in the case of filter-feeding organisms, such as molluscs, krill, sponges, etc.
Topics: Microplastics; Plastics; Polystyrenes; Water; Water Pollutants, Chemical
PubMed: 33743272
DOI: 10.1016/j.envpol.2021.116910 -
Cell Reports Oct 2022Intracellular chloride ion concentration ([Cl]) homeostasis is critical for excitatory/inhibitory balance and volume regulation in neurons. We quantitatively map...
Intracellular chloride ion concentration ([Cl]) homeostasis is critical for excitatory/inhibitory balance and volume regulation in neurons. We quantitatively map spatiotemporal dendritic [Cl] dynamics during N-methyl-d-aspartate (NMDA) excitotoxicity to determine how Cl changes contribute to localized dendritic swelling (blebbing) in stroke-like conditions. Whole-cell patch clamp electrophysiology combined with simultaneous fluorescence lifetime imaging (FLIM) of the Cl dye N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE; MQAE-FLIM) reliably report resting and dynamic [Cl] shifts in dendrites. NMDA application generates spatially restricted and persistent high [Cl] subdomains at dendritic blebs in a process that requires Ca influx and the subsequent opening of small-conductance Ca-activated K (SK) channels. We propose sustained and localized K efflux increased extracellular K concentrations ([K]) sufficiently at discrete regions to reverse K-Cl cotransporter (KCC2) transport and trigger synaptic swelling. Together, our data establish a mechanism for KCC2 to generate pathological [Cl] microdomains in blebbing with relevance for multiple neurological disorders.
Topics: Chlorides; N-Methylaspartate; Bromides; Symporters; Neurons
PubMed: 36288701
DOI: 10.1016/j.celrep.2022.111556 -
ACS Applied Polymer Materials Nov 2021Herein, a solvent-based green recycling procedure is reported for recycling thermoset epoxy resins (TERs) and carbon fiber reinforced epoxy composites (CFRECs) employing...
Herein, a solvent-based green recycling procedure is reported for recycling thermoset epoxy resins (TERs) and carbon fiber reinforced epoxy composites (CFRECs) employing ionic liquids (ILs) and alcohols under mild conditions. With melting points less than 100 °C, ILs are defined as organic salts, typically composed of bulky cations with organic or inorganic counteranions. As a result of their unique physical properties such as low vapor pressure, relatively high thermal stability, and multifunctional tunability, these solvents are often classified as "green solvents" as compared to traditional organic solvents. In this study, swelling and dissolution of TER are evaluated in the presence of pure alkyl-methyl-imidazolium ILs, alcohols, and various mixtures of these co-solvents to determine their swelling and depolymerization capacity at mild temperatures in the absence of catalysts. In these studies, three ILs with different alkyl lengths were evaluated: 1-butyl-3-methyl imidazolium chloride ([BMIm][Cl]), 1-hexyl-3-methyl imidazolium bromide ([HMIm][Br]), and 1-octyl-3-methyl imidazolium bromide ([OMIm][Br]) along with two alcohols: ethylene glycol (EG) and glycerol (Gly). The highest swelling capacity of TER at 150 °C was achieved by a combination of [BMIm][Cl] and EG. In addition, swelling and dissolution of TER were evaluated in the presence of several anion variants of 1-butyl-3-methyl-imidazolium ILs with EG. Complete dissolution of both TERs and CFRECs was achieved in 150 min (2.5 h) at 150 °C under atmospheric pressure. Finally, recovery and reuse of the recycled monomer after dissolution were examined. Recovered epoxy monomers employed to synthesize a recycled TER exhibited similar mechanical properties to the parent TER. In addition, it was demonstrated that carbon fibers could be successfully recovered from CFREC using the recycling method detailed in this manuscript.
PubMed: 34796334
DOI: 10.1021/acsapm.1c00896