Sodium-iodide symporter and its related solute carriers in thyroid cancer

The solute carrier (SLC) family is a large group of membrane transport proteins. Their dysfunction plays an important role in the pathogenesis of thyroid cancer. The most well-known SLC is the sodium-iodide symporter (NIS), also known as sodium/iodide co-transporter or solute carrier family 5 member 5 (SLC5A5) in thyroid cancer. The dysregulation of NIS in thyroid cancer is well documented. The role of NIS in the uptake of iodide is critical in the treatment of thyroid cancer, radioactive iodide (RAI) therapy in particular. In addition to NIS, other SLC members may affect the autophagy, proliferation, and apoptosis of thyroid cancer cells, indicating that an alteration in SLC members may affect different cellular events in the evolution of thyroid cancer. The expression of the SLC members may impact the uptake of chemicals by the thyroid, suggesting that targeting SLC members may be a promising therapeutic strategy in thyroid cancer.

Spontaneous Appearance of Triiodide Covering the Topmost Layer of the Iodide Solution Interface Without Photo-Oxidation

Ions containing iodine atoms at the vapor-aqueous solution interfaces critically affect aerosol growth and atmospheric chemistry due to their complex chemical nature and multivalency. While the surface propensity of iodide ions has been intensely discussed in the context of the Hofmeister series, the stability of various ions containing iodine atoms at the vapor-water interface has been debated. Here, we combine surface-specific sum-frequency generation (SFG) vibrational spectroscopy with ab initio molecular dynamics simulations to examine the extent to which iodide ions cover the aqueous surface. The SFG probe of the free O-D stretch mode of heavy water indicates that the free O-D group density decreases drastically at the interface when the bulk NaI concentration exceeds ∼2 M. The decrease in the free O-D group density is attributed to the spontaneous appearance of triiodide that covers the topmost interface rather than to the surface adsorption of iodide. This finding demonstrates that iodide is not surface-active, yet the highly surface-active triiodide is generated spontaneously at the water-air interface, even under dark and oxygen-free conditions. Our study provides an important first step toward clarifying iodine chemistry and pathways for aerosol formation.

The Iodine/Iodide/Starch Supramolecular Complex

The nature of the blue color in the iodine-starch reaction (or, in most cases, iodine-iodide-starch reaction, i.e., I2 as well as I- are typically present) has for decades elicited debate. The intensity of the color suggests a clear charge-transfer nature of the band at ~600 nm, and there is consensus regarding the fact that the hydrophobic interior of the amylose helix is the location where iodine binds. Three types of possible sources of charge transfer have been proposed: (1) chains of neutral I2 molecules, (2) chains of poly-iodine anions (complicated by the complex speciation of the I2-I- mixture), or (3) mixtures of I2 molecules and iodide or polyiodide anions. An extended literature review of the topic is provided here. According to the most recent data, the best candidate for the "blue complex" is an I2-I5--I2 unit, which is expected to occur in a repetitive manner inside the amylose helix.

Synergistic Zinc(II) and Formate Doping of Perovskites: Thermal Phase Stabilization of α-FAPbI3 and Enhanced Photoluminescence Lifetime of FA0.8MA0.2PbI3 up to 3.7 µs

Adding zinc (II) cations and formate anions improves the thermal phase stability of α-FAPbI3 materials, and the spin-coated thin films of such doped FAPbI3 (produced using MACl) show an increased emission lifetime of up to 3.7 μs on quartz (for FA0.8MA0.2PbI3). This work investigates the effects of zinc and formate on the phase stability and time-resolved photoluminescence of FAPbI3 perovskites for solar cell applications. Perovskite samples with varying concentrations of zinc and formate were made by incorporating different amounts of zinc formate and zinc iodide and were characterized with XRD. Doping levels of 1.7% Zn(II) and 1.0% formate (relative to Pb) seem optimal. The thermal phase stability of the doped perovskite powders (FAPbI3) and thin films (FA0.8MA0.2PbI3) was assessed. XRD of the thin films after 6 months shows only the alpha-phase. The time-resolved photoluminescence spectroscopy of the doped spin-coated perovskite samples (FA0.8MA0.2PbI3 produced using MACl) is reported. The results show that synergy between an anionic and a cationic dopant can take place, making the perovskite thermally more phase-stable (not converting to the yellow delta-phase) with a longer charge carrier lifetime. In order to produce good thin films by spin coating, the use of MACl was essential.

Co-Occurrence of Bromine and Iodine Species in US Drinking Water Sources That Can Impact Disinfection Byproduct Formation

Bromine and iodine species are precursors for forming disinfection byproducts in finished drinking waters. Our study incorporates spatial and temporal data to quantify concentrations of inorganic (bromide (Br-), iodide (I-), and iodate (IO3-)), organic, and total bromine (BrT) and iodine (IT) species from 286 drinking water sources and 7 wastewater effluents across the United States. Br- ranged from <5-7800 μg/L (median of 62 μg/L in surface water (SW) and 95 μg/L in groundwater (GW)). I- was detected in 41% of SW (1-72 μg/L, median = <1 μg/L) and 62% of GW (<1-250 μg/L, median = 3 μg/L) samples. The median Br-/I- ratio in SW and GW was 22 μg/μg and 16 μg/μg, respectively, in paired samples with detect Br- and I-. BrT existed primarily as Br-, while IT was present as I-, IO3-, and/or total organic iodine (TOI). Inorganic iodine species (I- and IO3-) were predominant in GW samples, accounting for 60-100% of IT; however, they contributed to only 20-50% of IT in SW samples. The unknown fraction of IT was attributed to TOI. In lakes, seasonal cycling of I-species was observed and was presumably due to algal productivity. Finally, Spearman Rank Correlation tests revealed a strong correlation between Br- and IT in SW (RBr-,IT = 0.83) following the log10 (Br-, μg/L) = 0.65 × log10 (IT, μg/L) - 0.17 relationship. Br- and I- in treated wastewater effluents (median Br- = 234 μg/L, median I- = 5 μg/L) were higher than drinking water sources.

Leaching of Copper Concentrates with Iodized Salts in a Saline Acid Medium: Part 2-Effect on Chloride Concentration and an Aerated System

To enhance the leaching of chalcopyrite concentrates, this study evaluated a new process for extracting copper using iodized solutions and sulfuric acid diluted in seawater without pressure or high temperatures. The work involved a leaching test carried out under various conditions by varying the concentrations of chloride ions, H2SO4, and an evenly distributed oxygen supply in an aeration system. It was demonstrated that Cl- ion addition could promote the chalcopyrite-leaching process. The leaching efficiency of copper reached 70% after 96 h. However, a chloride ion dosage excess can have the opposite effect on extraction, reducing copper recovery. XRD and SEM-EDS results showed that cuprous chloride (CuCl) was formed at high dosages (>0.5 M); meanwhile, at a lower dosage, elemental sulfur (S) was formed in the presence of sulfuric acid solution and seawater medium. In contrast, in an aerated system, surface roughness markedly increased due to continuous oxidation on the surface of the ore. This change in morphology and the high value of the redox potential, given by the aerated system and the acidic environment, allowed copper recovery of up to 70% after 96 h. The results showed that an aerated system is the most effective factor in chalcopyrite concentrate leaching.

An Interference-Free Voltammetric Method for the Detection of Sulfur Dioxide in Wine Based on a Boron-Doped Diamond Electrode and Reaction Electrochemistry

This paper describes a new, simple, and highly selective analytical technique for the detection of sulfur dioxide in wine, as a real sample with a relatively complicated matrix. The detection of the above analyte was based on the electrogeneration of iodine from iodide on a boron-doped diamond electrode, without modifications, in the presence of 0.1 mol dm-3 HClO4 as a supporting electrolyte. The electrogenerated iodine reacted with sulfur dioxide, forming iodide ions and sulfuric acid (i.e., a Bunsen reaction). The product of this reaction, the iodide ion, diffused back to the surface of the boron-doped diamond electrode and oxidized itself again. This chemical redox cycling enhanced the voltammetric response of the boron-doped diamond electrode. The selectivity of the determination was assured using NaOH and formaldehyde during sample preparation, and a blank was also measured and taken into account. The detection limit was estimated to be 10-6-10-7 mol dm-3. However, the content of sulfur dioxide in wine is significantly higher, which can lead to more accurate and reliable results.

Iodide-Induced Severe Encephalopathy: A Case Report and Literature Review

A physically independent and mentally competent 61-year-old gentleman was diagnosed with left upper alveolar spindle cell carcinoma. He underwent left infrastructure maxillectomy with reconstruction and had bismuth iodoform paraffin paste packed in the post-operative cavities. The patient subsequently exhibited labile emotions and acute delirium. Further investigation showed that his urine iodine level was highly elevated. He eventually made a full recovery and returned home.

Iodide-Enhanced Perovskite Nanozyme-Based Colorimetric Platform for Detection of Urinary Nuclear Matrix Protein 22

In the last decade, perovskite nanocrystals (PNCs) have brought extensive thinking owing to their excellent optical properties. Recently, we have uncovered the peroxidase-like activity of PNCs and used this for detecting many small molecules; however, the low enzymatic activity makes them unsuitable for fluorescence analysis, which is easily disturbed by the autofluorescence of biological media. This greatly limits their application in bioanalysis. Thus, the development of a method to facilely modulate the activity of PNCs for the instrument-free colorimetric detection is highly desirable. Herein, we demonstrated an iodide-enhanced perovskite nanozyme-based colorimetric platform for the visual assay of urinary nuclear matrix protein 22 (NMP22), a typical biomarker for the diagnosis of bladder cancer. We discovered that halogen could regulate the activity of perovskite nanozymes through a simple anion replacement reaction. Experimental analysis suggested that CsPbI₃ nanocrystals (NCs) displayed 24-fold higher catalytic efficiency than classical CsPbBr₃ NCs. As a proof-of-concept assay, the CsPbI₃ NCs could be explored into an immunoassay for the detection of NMP22 in clinical urine specimens, resulting in a low detection limit of 0.03 U/mL. This iodide-enhanced immunoassay deepens our understanding of perovskite nanozymes and also provides great potential for bioanalysis.

Iodide-Mediated Etching of Gold Nanostar for the Multicolor Visual Detection of Hydrogen Peroxide

A multicolor visual method for the detection of hydrogen peroxide (H₂O₂) was reported based on the iodide-mediated surface etching of gold nanostar (AuNS). First, AuNS was prepared by a seed-mediated method in a HEPES buffer. AuNS shows two different LSPR absorbance bands at 736 nm and 550 nm, respectively. Multicolor was generated by iodide-mediated surface etching of AuNS in the presence of H₂O₂. Under the optimized conditions, the absorption peak Δλ had a good linear relationship with the concentration of H₂O₂ with a linear range from 0.67~66.67 μmol L^-1, and the detection limit is 0.44 μmol L^-1. It can be used to detect residual H₂O₂ in tap water samples. This method offered a promising visual method for point-of-care testing of H₂O₂-related biomarkers.

Leaching of Copper Concentrate with Iodized Salts in a Saline Acid Medium: Part 1-Effect of Concentrations

One of the main problems in processing chalcopyrite ore with hydrometallurgical methods is its refractoriness, which is due to the formation of a layer that inhibits the contact of the ore with the leaching solution, thus reducing the dissolution rate. The main objective of this paper is to evaluate the leaching potential of iodide ions in copper extraction from chalcopyrite concentrate in an acidic seawater medium. Leaching tests were carried out in glass reactors stirred at 45 °C. Parameters such as iodide salt concentration and acidity were evaluated in ranges of 0-5000 ppm and 0-1.0 M, respectively. According to the results obtained, adding iodide ions to a medium acid enhances the leaching kinetics in the chalcopyrite concentrate, observing that it improves copper extraction at low concentrations of 100 ppm KI compared to high concentrations of 5000 ppm KI. As a result, part of the iodide required to oxidize copper tends to sublimate or is associated with other ions producing iodinated compounds such as CuI. Copper extraction reached 45% within the first 96 h, while at 216 h, it reached an extraction of close to 70% copper. The recovery rate improves at potentials between 600 and 650 mV, while at lower potentials, the copper extraction decreases. The mineral surface was analyzed using SEM/EDS and XRD analyses for the identification of precipitates on the surface, finding porous elemental sulfur and precipitated jarosite. An increase in iodide ions improves the leaching kinetics in the chalcopyrite concentrate, observing that it improves copper extraction at low concentrations of 100 ppm KI compared to high concentrations of 5000 ppm KI. As a result, part of the iodide required to oxidize copper tends to sublimate or is associated with other ions producing iodinated compounds such as CuI. Copper extraction reached 45% within the first 96 h, while at 216 h, it reached an extraction of close to 70% copper. The recovery rate improves at potentials between 600 and 650 mV, while at lower potentials, the copper extraction decreases. The mineral surface was analyzed using SEM/EDS and XRD analyses for the identification of precipitates on the surface, finding porous elemental sulfur and precipitated jarosite.

Iodide uptake by forest soils is principally related to the activity of extracellular oxidases

¹²⁹I is a nuclear fission decay product of concern because of its long half-life (16 Ma) and propensity to bioaccumulate. Microorganisms impact iodine mobility in soil systems by promoting iodination (covalent binding) of soil organic matter through processes that are not fully understood. Here, we examined iodide uptake by soils collected at two depths (0-10 and 10-20 cm) from 5 deciduous and coniferous forests in Japan and the United States. Autoclaved soils, and soils amended with an enzyme inhibitor (sodium azide) or an antibacterial agent (bronopol), bound significantly less ¹²⁵I tracer (93%, 81%, 61% decrease, respectively) than the untreated control soils, confirming a microbial role in soil iodide uptake. Correlation analyses identified the strongest significant correlation between ¹²⁵I uptake and three explanatory variables, actinobacteria soil biomass (p = 6.04E-04, 1.35E-02 for Kendall-Tau and regression analysis, respectively), soil nitrogen content (p = 4.86E-04, 4.24E-03), and soil oxidase enzyme activity at pH 7.0 using the substrate L-DOPA (p = 2.83E-03, 4.33E-04) and at pH 5.5 using the ABTS (p = 5.09E-03, 3.14E-03). Together, the results suggest that extracellular oxidases, primarily of bacterial origin, are the primary catalyst for soil iodination in aerobic, surface soils of deciduous and coniferous forests, and that soil N content may be indicative of the availability of binding sites for reactive iodine species.

On the Origin of the Blue Color in The Iodine/Iodide/Starch Supramolecular Complex

The nature of the blue color in the iodine-starch reaction is still a matter of debate. Some textbooks still invoke charge-transfer bands within a chain of neutral I₂ molecules inside the hydrophobic channel defined by the interior of the amylose helical structure. However, the consensus is that the interior of the helix is not altogether hydrophobic-and that a mixture of I₂ molecules and iodide anions reside there and are responsible for the intense charge-transfer bands that yield the blue color of the "iodine-starch complex". Indeed, iodide is a prerequisite of the reaction. However, some debate still exists regarding the nature of the iodine-iodine units inside the amylose helix. Species such as I₃^-, I₅^-, I₇^- etc. have been invoked. Here, we report UV-vis titration data and computational simulations using density functional theory (DFT) for the iodine/iodide chains as well as semiempirical (AM1, PM3) calculations of the amylose-iodine/iodide complexes, that (1) confirm that iodide is a pre-requisite for blue color formation in the iodine-starch system, (2) propose the nature of the complex to involve alternating sets of I₂ and I_x^- units, and (3) identify the nature of the charge-transfer bands as involving transfer from the I_x^- σ* orbitals (HOMO) to I₂ σ* LUMO orbitals. The best candidate for the "blue complex", based on DFT geometry optimizations and TD-DFT spectral simulations, is an I₂-I₅-I₂ unit, which is expected to occur in a repetitive manner inside the amylose helix.

Occurrence of Iodophenols in Aquatic Environments and the Deiodination of Organic Iodine with Ferrate(VI)

Toxic and odorous iodophenols are commonly identified as disinfection by-products (DBPs) in drinking water. Herein, ng/L levels of iodophenols were identified in river water, wastewater treatment plant effluent, and medical wastewater, with the simultaneous identification of μg/L to mg/L levels of iodide (I^-) and total organic iodine (TOI). Oxidation experiment suggested that the I^-, TOI, and iodophenols could be oxidized by ferrate [Fe(VI)], and more than 97% of TOI had been transformed into stable and nontoxic IO₃^-. Fe(VI) initially cleaved the C-I bond of iodophenols and led to the deiodination of iodophenols. The resulted I^- was swiftly oxidized into HOI and IO₃^-, with the intermediate phenolic products be further oxidized into lower molecular weight products. The Gibbs free energy change (ΔG) of the overall reaction was negative, indicating that the deiodination of iodophenols by Fe(VI) was spontaneous. In the disinfection of iodine-containing river water, ng/L levels of iodophenols and chloro-iodophenols formed in the reaction with NaClO/NH₂Cl, while Fe(VI) preoxidation was effective for inhibiting the formation of iodinated DBPs. Fe(VI) exhibited multiple functions for oxidizing organic iodine, abating their acute toxicity/cytotoxicity and controlling the formation of iodinated DBPs for the treatment of iodide/organic iodine-containing waters.

Halogenoderma: A Case Report and Review of the Literature

Halogenoderma (HD) is an uncommon dermatosis that develops following exposure to halogens such as iodide and bromide, referred to as iododerma and bromoderma, respectively. Here, we report the case of a 40-year-old male who presented with a three-week history of slightly itchy progressive skin lesions associated with low-grade fever and malaise. The patient had a history of using food supplements containing iodide and bromide for four months prior to the appearance of skin rashes. Skin examination revealed multiple crusted papules and nodules scattered on his face, neck, and trunk. A skin biopsy was taken from the lesions. The epidermis showed crustation, exocytosis of neutrophils, and multiple intraepidermal abscesses. The dermis showed heavy cellular infiltrates composed mainly of neutrophils. The skin lesions disappeared completely after the cessation of food supplements, along with the use of topical corticosteroids for a few weeks.

Facile Preparation of MCM-41/Ag2O Nanomaterials with High Iodide-Removal Efficiency

The elimination of iodide (I^-) from water is a tough subject due to its low adsorption tendency and high mobility. In this work, MCM-41/Ag₂O nanomaterials were prepared, characterized, and employed to adsorb I^- from water. The Ag₂O nanoparticles were dispersed homogeneously in the pores or at the surface of the MCM-41 support, and the Ag₂O nanoparticles in the pores had small particles sizes due to the confinement of the mesoporous channel. The prepared MCM-41/Ag₂O nanomaterials exhibited a higher specific surface area than previously reported Ag₂O-based composites. The adsorption of I^- by the nanomaterials was able to reach equilibrium at 180 min. The MCM-41/Ag₂O nanomaterials showed a better adsorption capacity per unit mass of Ag₂O than pure Ag₂O nanoparticles and previously reported Ag₂O-based composites prepared using other supports. Furthermore, the MCM-41/Ag₂O nanomaterials exhibited high selectivity for I^- in the presence of high concentrations of competitive anions, such as Cl^- or Br^-, and could function in a wide range of pH. The chemical reaction between Ag₂O and I^- and the surface adsorption were the main adsorption mechanisms. These results indicate that MCM-41/Ag₂O nanomaterials are a promising and efficient adsorbent material suitable for the removal of I^- for practical application.

Iodide Removal by Resorcinol-Formaldehyde Carbon Aerogels

The adsorption technique is widely used in water purification, and its efficiency can be significantly improved by target-specific adsorbent design. Research on iodine and its ion removal from water has attracted a great deal of interest due to increased concentrations in the environment and acute toxic effects, e.g., in human thyroid cells. In this work, the iodide removal performance of two high-surface-area resorcinol-formaldehyde-based carbon aerogels was studied under acidic conditions. The BET surface area was 790 m²/g (RF_ac) and 375 m²/g (RMF-GO), with a corresponding micropore ratio of 36 and 26%, respectively. Both aerogels showed outstanding adsorption capacity, exceeding the reported performance of other carbons and Ag-doped materials. Owing to its basic nature, the RMF-GO carbon aerogel showed higher I^- capacity, up to 97 mg/g, than the acidic RF_ac, which reached a capacity of 82 mg/g. The surface chemistry of the aerogels also played a distinct role in the removal. In terms of kinetics, RF_ac removed 60% of the iodide ions and RMF-GO 30% within 8 h. The removal kinetics was of the first order, with a half-life of 1.94 and 1.70 h, respectively.

Synchronous Moderate Oxidation and Adsorption on the Surface of γ-MnO2 for Efficient Iodide Removal from Water

Long-term exposure to excessive iodine via drinking water presents health risks. Moderate oxidation of iodide (I^-) to iodine (I₂) has a better iodine removal effect than excessive oxidation to iodate (IO₃^-). This study combines computational and experimental methods to construct a heterogeneous interface with synchronous I^- moderate oxidation and I₂ adsorption to increase the total iodine removal. Compared to other forms of crystal manganese dioxide (MnO₂), theoretical calculations predict that MnO₂ with a γ-crystal structure has the lowest adsorption energy, that is, -1.20 eV, and a slight overlap between the conduction and valence bands, which favors electron transfer between I^- and Mn(IV) and I₂ adsorption. Thus, γ-type MnO₂ was designed by adjusting the precursor Mn sources and hydrothermal reaction conditions. The liquid chromatography-inductively coupled plasma-mass spectrometry and high-performance liquid chromatography confirmed that the total iodine concentration in water decreased from 173.7 to 36.3 μg/L after 2 h, with 200 mg/L γ-MnO₂ dosage lower than the national standard of 0.1 mg/L. A minute proportion of I^- in water was converted to IO₃^- (approximately 1.1 μg/L). The current I^- adsorbent performed better than previously reported ones. During iodine removal, most of the I^- migrated from water to the surface of γ-MnO₂, and the ratio of I^- to I₂ was determined to be 1:0.6 by X-ray photoelectron spectroscopy. This study evaluates iodine species transformation and an optimum strategy for heterogeneous interface design; it is promising for treating high-iodine groundwater.

Comparative Evaluation of the Effects of Legacy and New Generation Perfluoralkyl Substances (PFAS) on Thyroid Cells In Vitro

BACKGROUND

Per- and poly-fluorinated alkyl substances (PFAS) are environment-persitent emerging endocrine disrupting chemicals raising health concerns worldwide. Exposure to PFAS has been associated with the imbalance of thyroid hormones. However, available studies addressing the cell mechanism underlying thyroid disrupting feature of legacy PFAS, such as perfluoro-octanoic acid (PFOA), perfluoro-octane-sulfonic acid (PFOS), and the new generation substitutes, such as C6O4, are still lacking. In this study the potential disrupting effect of PFOA, PFOS, and C6O4 on a murine thyroid cell model was assessed.

METHODS

A rat FRTL-5 cell line was used as the normal thyroid follicular cell model. Cell iodide-uptake, induced by thyroid stimulating hormone (TSH), was used to assess the functional impact of PFAS exposure on cell function. Tetrazolium salt-based cell viability assay and merocyanine 540-based cell staining were used to address the possible involvement of cell toxicity and membrane biophysical properties on altered cell function. The possible direct interaction of PFAS with TSH-receptor (TSH-R) was investigated by computer-based molecular docking and analysis of molecular dynamics. Evaluation of intracellular cAMP levels and gene expression analysis were used to validate the direct impairment of TSH-R-mediated downstream events upon PFAS exposure.

RESULTS

Different from PFOS or C6O4, exposure to PFOA at a concentration ≥ 10 ng/mL was associated with significant impairment of the iodide uptake upon TSH stimulation (respectively: basal 100.0 ± 19.0%, CTRL + TSH 188.9 ± 7.8%, PFOA 10 ng/mL + TSH 120.4 ± 20.9%, p= 0.030 vs CTRL + TSH; PFOA 100 ng/mL + TSH 115,6 ± 12,3% p= 0.017 vs CTRL + TSH). No impairment of cell viability or membrane stability was observed. Computational analysis showed a possible direct differential interaction of C6O4, PFOA, and PFOS on a same binding site of the extracellular domain of TSH-R. Finally, exposure to PFOA was associated with a significant reduction of downstream intracellular cAMP levels and both sodium-iodide transporter and thyroperoxidase gene expression upon TSH-R stimulation.

CONCLUSIONS

Our data suggest that legacy and new generation PFAS can differentially influence TSH dependent signaling pathways through the direct interaction with TSH-R.

Fate and transformation of iodine species during Mn(VII)/sulfite treatment in iodide-containing water

During oxidative treatment of iodide (I^- )-containing waters, I^- is easy to be oxidized into hypoiodous acid (HOI) by various oxidants and the further reaction of HOI with organic compounds can lead to the formation of iodinated disinfection by-products (I-DBPs). Oxidation of HOI to iodate (IO₃ ^- ) or reduction of HOI to I^- has been proposed to reduce the formation of I-DBPs. Because the reaction of HOI with sulfite proceeds rapidly, this study examined the fate of iodine and the formation of I-DBPs in Mn(VII)/sulfite process. Results showed that I^- was oxidized to HOI but the further formation of IO₃ ^- was suppressed due to the fast reduction of HOI to I^- by sulfite. The reactions of HOI with SO₃ ^2- and IO^- with SO₃ ^2- are the major pathways with species-specific second-order rate constants determined to be 1.12 × 10⁵  M^-1  s^-1 and 9.43 × 10⁷  M^-1  s^-1 , respectively. The rapid reaction of HOI with sulfite plays an essential role in minimizing the formation of iodinated products in HOI- and phenol-containing solutions. The toxic risk analysis showed that the toxicity of the generated DBPs from Mn(VII)/sulfite pre-oxidation followed by chlorination only changed slightly. PRACTITIONER POINTS: The decay of I^- was negligible in Mn(VII)/sulfite process. The rapid reaction of HOI with SO₃ ^2- resulted in the negligible generation of IO₃ ^- . Mn(VII)/sulfite process exerted slight influence on the formation of I-DBPs. Mn(VII)/sulfite process is promising for the pretreatment of I^- -containing water.

Nutritional Supplementation Reduces Lesion Size and Neuroinflammation in a Sex-Dependent Manner in a Mouse Model of Perinatal Hypoxic-Ischemic Brain Injury

Perinatal hypoxia-ischemia (HI) is a major cause of neonatal brain injury, leading to long-term neurological impairments. Medical nutrition can be rapidly implemented in the clinic, making it a viable intervention to improve neurodevelopment after injury. The omega-3 (n-3) fatty acids docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3), uridine monophosphate (UMP) and choline have previously been shown in rodents to synergistically enhance brain phospholipids, synaptic components and cognitive performance. The objective of this study was to test the efficacy of an experimental diet containing DHA, EPA, UMP, choline, iodide, zinc, and vitamin B12 in a mouse model of perinatal HI. Male and female C57Bl/6 mice received the experimental diet or an isocaloric control diet from birth. Hypoxic ischemic encephalopathy was induced on postnatal day 9 by ligation of the right common carotid artery and systemic hypoxia. To assess the effects of the experimental diet on long-term motor and cognitive outcome, mice were subjected to a behavioral test battery. Lesion size, neuroinflammation, brain fatty acids and phospholipids were analyzed at 15 weeks after HI. The experimental diet reduced lesion size and neuroinflammation specifically in males. In both sexes, brain n-3 fatty acids were increased after receiving the experimental diet. The experimental diet also improved novel object recognition, but no significant effects on motor performance were observed. Current data indicates that early life nutritional supplementation with a combination of DHA, EPA, UMP, choline, iodide, zinc, and vitamin B12 may provide neuroprotection after perinatal HI.

Production of Methyl-Iodide in the Environment

Iodine is an essential micronutrient for most of the living beings, including humans. Besides its indispensable role in animals, it also plays an important role in the environment. It undergoes several chemical and biological transformations resulting in the production of volatile methylated iodides, which play a key role in the iodine's global geochemical cycle. Since it can also mitigate the process of climate change, it is reasonable to study its biogeochemistry. Therefore, the aim of this review is to provide information on its origin, global fluxes and mechanisms of production in the environment.

Rhodium-Iodide Complex on a Catalytically Active SiO2 Surface for One-Pot Hydrosilylation-CO2 Cycloaddition

In this study, a novel Rh-iodide complex was synthesized through a surface reaction between an immobilized Rh cyclooctadiene complex and alkylammonium iodide (N⁺ I^- ) on SiO₂ . In the presence of ammonium cations, the SiO₂ -supported Rh-iodide complex could be effectively used for the one-pot synthesis of various silylcarbonate derivatives starting from epoxy olefins, hydrosilanes, and CO₂ . The maximum turnover numbers (TONs) for the hydrosilylation reaction and the CO₂ cycloaddition were 7600 (Rh) and 130 (N⁺ I^- ), respectively. The catalyst exhibited much higher performance for hydrosilylation than solely the Rh complex on SiO₂ . The mechanism of the Rh-catalyzed hydrosilylation reaction and the local structure of Rh, which is affected by the co-immobilized N⁺ I^- , were investigated by using Rh and I K-edge XAFS and XPS. Analysis of the XAFS profiles indicated the presence of a Rh-I bond. The Rh unit was in its electron-rich state. Curve-fitting analysis of the Rh K-edge EXAFS profiles suggests dissociation of the cycloocta-1,5-diene (COD) ligand from the Rh center. Results from spectroscopic and kinetic analyses revealed that the high activity of the catalyst (during hydrosilylation) could be attributed to a decrease in steric hindrance and the electron-rich state of the Rh. The decrease in the steric hindrance could be attributed to the absence of COD, and the electron-rich state promoted the oxidative addition of Si-H. To the best of our knowledge, this is the first example of a one-pot silylcarbonate synthesis as well as a determination of a novel surface Rh-iodide complex and its catalysis.

Crystal structures of Zn(cyclam)I2 (second monoclinic polymorph) and Zn(cyclam)I(I3)

The crystal of the first title compound contains five-coordinate [Zn(L)I]⁺ (L = cyclam) cations and non-coordinated iodide anions; the extended structure is consolidated by N—H⋯I and N—H⋯(I,I) hydrogen bonds. The crystals of the second title compound consist of chains of [Zn(L)I]⁺ units and triiodide counter-ions but without significant hydrogen-bonding inter­actions.

The asymmetric unit of the first title compound iodido­(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ⁴N¹,N⁴,N⁸,N¹¹)zinc(II) iodide, [ZnI(C₁₀H₂₄N₄)]I, I, consists of the zinc–cyclam macrocyclic cation with one iodide anion coordinated to the metal ion [Zn—I = 2.6619 (5) Å] and the second present as a counter-ion. The asymmetric unit of the second title compound iodido­(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ⁴N¹,N⁴,N⁸,N¹¹)zinc(II) triiodide, [ZnI(C₁₀H₂₄N₄)]I₃, II, consists of half of the centrosymmetric macrocyclic cation, in which the Zn^II ion coordinated to an iodide anion [Zn—I = 2.766 (2) Å] is disordered over two positions [Zn⋯Zn = 0.810 (3) Å], and of the two halves of the crystallographically non-equivalent, non-coordinated, centrosymmetric triiodide anions. In both compounds, the N,N,N,N-tetra­dentate macrocyclic ligand is present in the most energetically favored trans-III conformation. In the crystals of I, the [Zn(C₁₀H₂₄N₄)I]⁺ cations and the non-coordinated iodide anions are linked by N—H⋯I and bifurcated N—H⋯(I,I) hydrogen bonds, resulting in the formation of two-dimensional networks lying parallel to the (001) and (101) planes. In contrast, the crystals of II are built up from infinite chains of the five-coordinate macrocyclic units arranged along the b-axis direction and perpendicular sheets formed of the triiodide counter-ions without significant hydrogen bonding between them.

The complex regulation of NIS expression and activity in thyroid and extrathyroidal tissues

The sodium/iodide symporter (NIS) is an intrinsic plasma membrane protein that mediates active iodide transport into the thyroid gland and into several extrathyroidal tissues. NIS-mediated iodide uptake plays a pivotal role in the biosynthesis of thyroid hormones, of which iodide is an essential constituent. For 80 years, radioiodide has been used for the diagnosis and treatment of thyroid cancer, a successful theranostic agent that is extending its use to extrathyroidal malignancies. The purpose of this review is to focus on the most recent findings regarding the mechanisms that regulate NIS both in thyroid and extra-thyroidal tissues. Among other issues, we discuss the different transcriptional regulatory elements that govern NIS transcription in different tissues, the epigenetic modifications that regulate its expression, and the role that miRNAs play in fine-tuning NIS after being transcribed. A review on how hormones, cytokines, and iodide itself regulate NIS is provided. We also review the present stage of understanding NIS dysregulation in cancer, occupied mainly by convergent signaling pathways and by new insights in the route that NIS follows through different subcellular compartments to the plasma membrane. Furthermore, we cover NIS distribution and function in the increasing number of extrathyroidal tissues that express the symporter, as well as the role that NIS plays in tumor progression independently of its transport activity.

Poly(ethylene glycol) Methyl Ether Methacrylate-bonded Stationary Phase in Ion Chromatography and Its Application to Seawater Samples

A fast and simple ion chromatographic method for the determination of iodide in seawater is reported using poly(ethylene glycol) methyl ether methacrylate-bonded stationary phase. Poly(ethylene glycol) methyl ether methacrylate was reacted with primary amino groups of aminopropylsilica in N,N-dimethylformamide at 80°C. The prepared stationary phases were evaluated by analyzing several inorganic anions and the retention behavior was observed. Various chromatographic parameters were optimized for the separation of these anions. Although there were no ion-exchange sites on the resulted stationary phases, the results obtained suggested that an ion-exchange mechanism was involved in the retention of analyte anions. With 0.15 μL injection, the limit of quantitation of iodide was 26 μg L^-1 when 200 mM NaCl was selected as the eluent. This stationary phase was applied to the analysis of direct and fast determination of iodide in real seawater samples successfully with the recovery rates of 98.1 and 104.9%.

A Multi-Sensor System for Sea Water Iodide Monitoring and Seafood Quality Assurance: Proof-of-Concept Study

Iodine is a trace chemical element fundamental for a healthy human organism. Iodine deficiency affects about 2 billion people worldwide causing from mild to severe neurological impairment, especially in children. Nevertheless, an adequate nutritional intake is considered the best approach to prevent such disorders. Iodine is present in seawater and seafood, and its common forms in the diet are iodide and iodate; most iodide in seawater is caused by the biological reduction of the thermodynamically stable iodate species. On this basis, a multisensor instrument which is able to perform a multidimensional assessment, evaluating iodide content in seawater and seafood (via an electrochemical sensor) and discriminating when the seafood is fresh or defrosted quality (via a Quartz Micro balance (QMB)-based volatile and gas sensor), is strategic for seafood quality assurance. Moreover, an electronic interface has been opportunely designed and simulated for a low-power portable release of the device, which should be able to identify seafood over or under an iodide threshold previously selected. The electrochemical sensor has been successfully calibrated in the range 10–640 μg/L, obtaining a root mean square error in cross validation (RMSECV) of only 1.6 μg/L. Fresh and defrosted samples of cod, sea bream and blue whiting fish have been correctly discriminated. This proof-of-concept work has demonstrated the feasibility of the proposed application which must be replicated in a real scenario.

Iodide-induced sialadenitis following percutaneous coronary intervention: A case report

Iodide-induced sialadenitis is a rapid, painless enlargement of salivary glands following administration of iodine-based contrast agents. It has been reported numerous times in the literature; however, the pathogenesis remains unclear. This case report demonstrates how this may present following a coronary angiogram.

The Effect of Sodium Iodide on Stromal Loading, Distribution and Degradation of Riboflavin in a Rabbit Model of Transepithelial Corneal Crosslinking

Purpose

To evaluate effects of sodium iodide (NaI) on riboflavin concentration in corneal stroma before and during ultraviolet A (UVA) light exposure using a novel transepithelial corneal collagen crosslinking (CXL) procedure (EpiSmart CXL system, CXL Ophthalmics, Encinitas CA).

Methods

Riboflavin solutions with NaI (Ribostat, CXL Ophthalmics, Encinitas CA) and without NaI were used for CXL in rabbits using EpiSmart. A pilot study determined sufficient riboflavin loading time. Four rabbits were dosed and monitored. Riboflavin fluorescence intensity was assessed from masked slit-lamp photos. A 12 min loading time was selected. Sixteen additional rabbits received the two formulae in contralateral eyes for CXL. Riboflavin uptake was assessed at 0, 10, 15, 20, 25, and 30 min of UVA exposure using a scale for riboflavin fluorescence previously validated against stromal concentration. Post sacrifice, corneal stromal samples were analyzed for concentrations of riboflavin and riboflavin 5ʹ-phosphate.

Results

Eyes dosed with NaI riboflavin had higher riboflavin grades compared to eyes dosed with the NaI-free riboflavin formulation immediately after riboflavin loading and persisting throughout UVA exposure, with significantly higher (P < 0.01 to < 0.05) riboflavin grades from 15 through 25 min of UVA exposure. Riboflavin grades decreased more slowly in eyes dosed with NaI riboflavin through 25 minutes of UVA exposure. Minor conjunctival irritation was noted with or without NaI.

Conclusion

The addition of NaI to riboflavin solution is associated with increased riboflavin concentration in corneal stroma throughout a clinically relevant time course of UVA exposure. This effect may be a combination of enhanced epithelial penetration and reduced riboflavin photodegradation and should enhance intrastromal crosslinking.

Iodide-Mediated Rapid and Sensitive Surface Etching of Gold Nanostars for Biosensing

Iodide-mediated surface etching can tailor the surface plasmon resonance of gold nanostars through etching of the high-energy facets of the nanoparticle protrusions in a rapid and sensitive way. By exploring the underlying mechanisms of this etching and the key parameters influencing it (such as iodide, oxygen, pH, and temperature), we show its potential in a sensitive biosensing system. Horseradish peroxidase-catalyzed oxidation of iodide enables control of the etching of gold nanostars to spherical gold nanoparticles, where the resulting spectral shift in the surface plasmon resonance yields a distinct color change of the solution. We further develop this enzyme-modulated surface etching of gold nanostars into a versatile platform for plasmonic immunoassays, where a high sensitivity is possible by signal amplification via magnetic beads and click chemistry.

Marine iodine emissions in a changing world

Iodine is a critical trace element involved in many diverse and important processes in the Earth system. The importance of iodine for human health has been known for over a century, with low iodine in the diet being linked to goitre, cretinism and neonatal death. Research over the last few decades has shown that iodine has significant impacts on tropospheric photochemistry, ultimately impacting climate by reducing the radiative forcing of ozone (O₃) and air quality by reducing extreme O₃ concentrations in polluted regions. Iodine is naturally present in the ocean, predominantly as aqueous iodide and iodate. The rapid reaction of sea-surface iodide with O₃ is believed to be the largest single source of gaseous iodine to the atmosphere. Due to increased anthropogenic O₃, this release of iodine is believed to have increased dramatically over the twentieth century, by as much as a factor of 3. Uncertainties in the marine iodine distribution and global cycle are, however, major constraints in the effective prediction of how the emissions of iodine and its biogeochemical cycle may change in the future or have changed in the past. Here, we present a synthesis of recent results by our team and others which bring a fresh perspective to understanding the global iodine biogeochemical cycle. In particular, we suggest that future climate-induced oceanographic changes could result in a significant change in aqueous iodide concentrations in the surface ocean, with implications for atmospheric air quality and climate.

Iodine Biofortification of Apples and Pears in an Orchard Using Foliar Sprays of Different Composition

Many people across the world suffer from iodine (I) deficiency and related diseases. The I content in plant-based foods is particularly low, but can be enhanced by agronomic biofortification. Therefore, in this study two field experiments were conducted under orchard conditions to assess the potential of I biofortification of apples and pears by foliar fertilization. Fruit trees were sprayed at various times during the growing season with solutions containing I in different concentrations and forms. In addition, tests were carried out to establish whether the effect of I sprays can be improved by co-application of potassium nitrate (KNO3) and sodium selenate (Na2SeO4). Iodine accumulation in apple and pear fruits was dose-dependent, with a stronger response to potassium iodide (KI) than potassium iodate (KIO3). In freshly harvested apple and pear fruits, 51% and 75% of the biofortified iodine was localized in the fruit peel, respectively. The remaining I was translocated into the fruit flesh, with a maximum of 3% reaching the core. Washing apples and pears with running deionized water reduced their I content by 14%. To achieve the targeted accumulation level of 50-100 μg I per 100 g fresh mass in washed and unpeeled fruits, foliar fertilization of 1.5 kg I per hectare and meter canopy height was required when KIO3 was applied. The addition of KNO3 and Na2SeO4 to I-containing spray solutions did not affect the I content in fruits. However, the application of KNO3 increased the total soluble solids content of the fruits by up to 1.0 °Brix compared to the control, and Na2SeO4 in the spray solution increased the fruit selenium (Se) content. Iodine sprays caused leaf necrosis, but without affecting the development and marketing quality of the fruits. Even after three months of cold storage, no adverse effects of I fertilization on general fruit characteristics were observed, however, I content of apples decreased by 20%.

Ultrasensitive Visual Detection of Glucose in Urine Based on the Iodide-Promoted Etching of Gold Bipyramids

Blood glucose monitoring is an essential but painful component of diabetes management, so it is urgent to develop simple, convenient, and noninvasive glucose monitoring methods as alternatives. Because the glucose level in urine is directly related to the blood glucose, urine can be an alternative for blood glucose monitoring. Herein, we report the development of a new and highly sensitive noninvasive colorimetric assay to detect the glucose content in urine samples using gold bipyramids (GBPs). The principle of this method is to utilize hydrogen peroxide (H₂O₂), the oxidation product of glucose, to etch GBPs, where the urine glucose will be quantified based on the displacement of the absorption peak of GBPs. The unique morphology (sharp tips) and etching mechanism (from tips) of GBPs determine the high sensitivity of this assay. Under optimal conditions, this colorimetric assay shows a dynamic range of 0.5-250 μM and a detection limit of 0.34 μM for artificial urine samples. This detection capability is ideal when sample dilution is necessary. Another advantage is that the color change of the GBP solution in this assay is convenient for the visual readout of the urine glucose semiquantitatively by the naked eye. Furthermore, it has been demonstrated here that the iodide ion has the horseradish peroxidase (HRP) activity and can be used alone to promote the reduction reaction of H₂O₂, which eliminates the use of HRP enzymes, simplifies the reaction, and reduces costs. The role of iodide ions has been studied and mainly attributed as a catalyst with I₂ as the reaction intermediate, which reduced the activation energy for the reduction of H₂O₂.

Polyhydrazide-Based Organic Nanotubes as Efficient and Selective Artificial Iodide Channels

Reported herein is a series of pore-containing polymeric nanotubes based on a hydrogen-bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of about a 6.5 Å diameter, mediate highly efficient transport of diverse types of anions, rather than cations, across lipid membranes. The reported polymer channel, having an average molecular weight of 18.2 kDa and 3.6 nm in helical height, exhibits the highest anion-transport activities for iodide (EC50 =0.042 μm or 0.028 mol % relative to lipid), whcih is transported 10 times more efficiently than chlorides (EC50 =0.47 μm). Notably, even in cholesterol-rich environment, iodide transport activity remains high with an EC50 of 0.37 μm. Molecular dynamics simulation studies confirm that the channel is highly selective for anions and that such anion selectivity arises from a positive electrostatic potential of the central lumen rendered by the interior-pointing methyl groups.

Optical Properties, Morphology, and Stability of Iodide-Passivated Lead Sulfide Quantum Dots

Iodide atomic surface passivation of lead chalcogenides has spawned a race in efficiency of quantum dot (QD)-based optoelectronic devices. Further development of QD applications requires a deeper understanding of the passivation mechanisms. In the first part of the current study, we compare optics and electrophysical properties of lead sulfide (PbS) QDs with iodine ligands, obtained from different iodine sources. Methylammonium iodide (MAI), lead iodide (PbI2), and tetrabutylammonium iodide (TBAI) were used as iodine precursors. Using ultraviolet photoelectron spectroscopy, we show that different iodide sources change the QD HOMO/LUMO levels, allowing their fine tuning. AFM measurements suggest that colloidally-passivated QDs result in formation of more uniform thin films in one-step deposition. The second part of this paper is devoted to the PbS QDs with colloidally-exchanged shells (i.e., made from MAI and PbI2). We especially focus on QD optical properties and their stability during storage in ambient conditions. Colloidal lead iodide treatment is found to reduce the QD film resistivity and improve photoluminescence quantum yield (PLQY). At the same time stability of such QDs is reduced. MAI-treated QDs are found to be more stable in the ambient conditions but tend to agglomerate, which leads to undesirable changes in their optics.

Crystal structure and Hirshfeld surface analysis of di-iodido-{N'-[(E)-(phen-yl)(pyridin-2-yl-κN)methylidene]pyridine-2-carbohydrazide-κ2 N',O}cadmium(II)

In each of the two independent mol-ecules in the asymmetric unit of the title compound, [CdI2(C18H14N4O)], the N,O,N'-tridentate N'-[(E)-(phen-yl)(pyridin-2-yl-κN)methyl-idene]pyridine-2-carbohydrazide ligand and two iodide anions form an I2N2O penta-coordination sphere, with a distorted square-pyramidal geometry, with an I atom in the apical position. Both mol-ecules feature an intra-molecular N-H⋯N hydrogen bond. In the crystal, weak aromatic π-π stacking inter-actions [centroid-centroid separation = 3.830 (2) Å] link the mol-ecules into dimers.

Mechanisms of Iodide⁻Triiodide Exchange Reactions in Ionic Liquids: A Reactive Molecular-Dynamics Exploration

Efficient charge transport has been observed in iodine-doped, iodide-based room-temperature ionic liquids, yielding high ionic conductivity. To elucidate preferred mechanistic pathways for the iodide ( I - )-to-triiodide ( I 3 - ) exchange reactions, we have performed 10 ns reactive molecular-dynamics calculations in the liquid state for 1-butyl-3-methylimidazolium iodide ([BMIM][I]) at 450 to 750 K. Energy-barrier distributions for the iodine-swapping process were determined as a function of temperature, employing a charge-reassignment scheme drawn in part from electronic-structure calculations. Bond-exchange events were observed with rate-determining energy barriers ranging from ~0.19 to 0.23 ± 0.06 eV at 750 and 450 K, respectively, with an approximately Arrhenius temperature dependence for iodine self-diffusivity and reaction kinetics, although diffusion dominates/limits the bond-exchange events. This charge transfer is not dissimilar in energetics to those in solid-state superionic conductors.

Facile Synthesis of Pd Nanocubes with Assistant of Iodide and Investigation of Their Electrocatalytic Performances Towards Formic Acid Oxidation

This article presents a facile, one-pot method using the aqueous phase for the synthesis of high-quality Pd nanocubes. In this study, Pd chloride was used as the precursor, sodium iodide as capping agent, and poly(vinylpyrrolidone) as surfactant and reducing agent. The effects of different halogens on the morphology of Pd nanocrystals were investigated. The results showed that, in this synthesis system, the selection and proper amount of sodium iodide was essential to the preparation of high-quality Pd nanocubes. When iodide was replaced by other halogens (such as bromide and chloride), Pd nanocrystals with cubic morphology could not be obtained. In addition, we have found that NaBH₄ can be used to efficiently remove inorganic covers, such as iodide, from the surface of Pd nanoparticles as synthesized. The Pd nanoparticles obtained were employed as electro-catalysts for formic acid oxidation, and they exhibited excellent catalytic activity and good stability towards this reaction.

COMPARISON OF TWO IODINE QUANTIFICATION METHODS IN AN ARTIFICIAL SEAWATER SYSTEM HOUSING WHITE-SPOTTED BAMBOO SHARKS ( CHILOSCYLLIUM PLAGIOSUM)

Iodine is an essential micronutrient for elasmobranchs in order to prevent goiter. Preventing goiter requires bioavailable iodide: either oral iodide or maintaining adequate aquarium water iodide concentrations. The objective of this study was to determine how oral and water supplementation affected iodine (I₂) and iodide (I^-) concentrations in artificial seawater aquaria housing captive white-spotted bamboo sharks ( Chiloscyllium plagiosum). Daily water samples were collected and free iodine (I₂) was determined using ultraviolet-absorbance spectrophotometry (a relatively simple in-house assay) and total iodide (I^-) via liquid chromatography (a more time- and expertise-intense quantification method) to learn the effects of supplementation. One water system received iodine and iodide supplementation in the form of 5% Lugol's iodine solution added directly to the water, while a second water system received no supplementation. In addition, one tank of sharks in each water system received oral iodide supplementation. Results indicated that oral supplementation provides greater increases in water concentrations of bioavailable iodide (I^-) than direct water supplementation. In addition, the chromatographic results suggested that iodide is present in higher concentrations in the systems not receiving water supplementation. Increased iodide concentrations were detected in water samples after water changes and after oral iodide supplementation was administered, but total iodine (I₂) concentration changes were not detectable within the same time frame.

WDR-23 and SKN-1/Nrf2 Coordinate with the BLI-3 Dual Oxidase in Response to Iodide-Triggered Oxidative Stress

Animals utilize conserved mechanisms to regulate oxidative stress. The C. elegans SKN-1 protein is homologous to the vertebrate Nrf (NF-E2-related factor) family of cap 'n' collar (CnC) transcription factors and functions as a core regulator of xenobiotic and oxidative stress responses. The WD40 repeat-containing protein WDR-23 is a key negative regulator of SKN-1 activity. We previously found that the oxidative stress induced by excess iodide can be relieved by loss of function in the BLI-3/TSP-15/DOXA-1 dual oxidase complex. To further understand the molecular mechanism of this process, we screened for new mutants that can survive in excess iodide and identified gain-of-function mutations in skn-1 and loss-of-function mutations in wdr-23 The SKN-1C isoform functions in the hypodermis to affect animal's response to excess iodide, while the SKN-1A isoform appears to play a minor role. wdr-23(lf) can interact with bli-3 mutations in a manner different from skn-1(gf) Transcriptome studies suggest that excess iodide causes developmental arrest largely independent of changes in gene expression, and wdr-23(lf) could affect the expression of a subset of genes by a mechanism different from SKN-1 activation. We propose that WDR-23 and SKN-1 coordinate with the BLI-3/TSP-15/DOXA-1 dual oxidase complex in response to iodide-triggered oxidative stress.

Bisphenol A increases hydrogen peroxide generation by thyrocytes both in vivo and in vitro

Bisphenol A (BPA) is the most common monomer in polycarbonate plastics and an endocrine disruptor. Though some effects of BPA on thyroid hormone (TH) synthesis and action have been described, the impact of this compound on thyroid H2O2 generation remains elusive. H2O2 is a reactive oxygen species (ROS) which could have deleterious effect on thyrocytes if in excess. Therefore, herein we aimed at evaluating the effect of BPA exposition both in vivo and in vitro on H2O2 generation in thyrocytes, besides other essential steps for TH synthesis. Female Wistar rats were treated with vehicle (control) or BPA 40 mg/Kg BW for 15 days, by gavage. We then evaluated thyroid iodide uptake, mediated by sodium-iodide symporter (NIS), thyroperoxidase (TPO) and dual oxidase (DOUX) activities (H2O2 generation). Hydrogen peroxide generation was increased, while iodide uptake and TPO activity were reduced by BPA exposition. We have also incubated the rat thyroid cell line PCCL3 with 10-9 M BPA and evaluated Nis and Duox mRNA levels, besides H2O2 generation. Similar to that found in vivo, BPA treatment also led to increased H2O2 generation in PCCL3. Nis mRNA levels were reduced and Duox2 mRNA levels were increased in BPA-exposed cells. To evaluate the importance of oxidative stress on BPA-induced Nis reduction, PCCL3 was treated with BPA in association to n-acetylcysteine, an antioxidant, which reversed the effect of BPA on Nis. Our data suggest that BPA increases ROS production in thyrocytes, what could lead to oxidative damage thus possibly predisposing to thyroid disease.

Potentiometric Sensors for Iodide and Bromide Based on Pt(II)-Porphyrin

Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) was used in the construction of new ion-selective sensors. The potentiometric response characteristics (slope and selectivity) of iodide and bromide-selective electrodes based on (PtTMeOPP) metalloporphyrin in o-nitrophenyloctylether (NPOE), dioctylphtalate (DOP) and dioctylsebacate (DOS) plasticized poly(vinyl chloride) membranes are compared. The best results were obtained for the membranes plasticized with DOP and NPOE. The sensors have linear responses with near-Nernstian slopes toward bromide and iodide ions and good selectivity. The membrane plasticized with NPOE was electrochemically characterized using the EIS method to determine its water absorption and the diffusion coefficient into the membrane.

Oxidative stress-mediated autophagic cell death participates in the neurotoxic effect on SH-SY5Y cells induced by excessive iodide

Excessive iodide could induce intellectual damage in children, which has attracted broad attention. To investigate the neurotoxic effect of iodide and its mechanism, a human dopaminergic neuroblastoma cell line (SH-SY5Y) was treated with different concentrations of potassium iodide (KI). The results showed that excessive iodide could decrease cell viability, reduce glutathione (GSH) and superoxide dismutase (SOD), and increase the degree of autophagy (by changing the cellular ultrastructure and raising the autophagy-related mRNA and protein expression of LC3, Beclin1, and p62), which were correlated with the immunofluorescence labeling. Furthermore, treatment with the autophagy inhibitor 3-methyladenine (3MA), antioxidant N-acetylcysteine (NAC) and 30 mM KI for 24 h was conducted in the following research. 3MA significantly decreased autophagy-related mRNA and protein expression and improved cell viability, indicating that excess iodide induced autophagic cell death. In addition, oxidative stress regulated autophagy, reflected by the results that NAC decreased the mRNA and protein expression of LC3, Beclin1, and p62. In summary, autophagic cell death mediated by oxidative stress may participate in excessive iodide-induced SH-SY5Y cell death.

Three-dimensional organic-inorganic hybrid sodium halide perovskite: C4H12N2·NaI3 and a hydrogen-bonded supramolecular three-dimensional network in 3C4H12N2·NaI4·3I·H2O

The rational selection of ligands is vitally important in the construction of new organic-inorganic hybrid three-dimensional perovskite complexes. As part of an exploration of perovskite-type materials, two new Na-I compounds based on the piperazine ligand, namely poly[piperazinediium [tri-μ-iodido-sodium]], {(C4H12N2)[NaI3]}n, 1, and catena-poly[tris(piperazinediium) [[triiodidosodium]-μ-iodido] triiodide monohydrate], {(C4H12N2)3[NaI4]I3·H2O}n, 2, have been synthesized by adjusting the stoichiometric ratio of sodium iodide and piperazine, and were characterized by single-crystal X-ray diffraction. In the crystal structures of 1 and 2, each NaI cation is linked to six I atoms, but the compounds show completely different configurations. In 1, the structure includes a perovskite-like array of vertex-sharing NaI6 octahedra stretching along the direction of the three axes, and each piperazinediium dication is enclosed in the NaI3 perovskite cage. However, in 2, each NaI atom bridges a single I atom to form a one-dimensional linear chain, and complex intermolecular hydrogen bonds connect these one-dimensional chains into a three-dimensional supramolecular network.

NFE2-Related Transcription Factor 2 Coordinates Antioxidant Defense with Thyroglobulin Production and Iodination in the Thyroid Gland

BACKGROUND

The thyroid gland has a special relationship with oxidative stress. While generation of oxidative substances is part of normal iodide metabolism during thyroid hormone synthesis, the gland must also defend itself against excessive oxidation in order to maintain normal function. Antioxidant and detoxification enzymes aid thyroid cells to maintain homeostasis by ameliorating oxidative insults, including during exposure to excess iodide, but the factors that coordinate their expression with the cellular redox status are not known. The antioxidant response system comprising the ubiquitously expressed NFE2-related transcription factor 2 (Nrf2) and its redox-sensitive cytoplasmic inhibitor Kelch-like ECH-associated protein 1 (Keap1) defends tissues against oxidative stress, thereby protecting against pathologies that relate to DNA, protein, and/or lipid oxidative damage. Thus, it was hypothesized that Nrf2 should also have important roles in maintaining thyroid homeostasis.

METHODS

Ubiquitous and thyroid-specific male C57BL6J Nrf2 knockout (Nrf2-KO) mice were studied. Plasma and thyroids were harvested for evaluation of thyroid function tests by radioimmunoassays and of gene and protein expression by real-time polymerase chain reaction and immunoblotting, respectively. Nrf2-KO and Keap1-KO clones of the PCCL3 rat thyroid follicular cell line were generated using CRISPR/Cas9 technology and were used for gene and protein expression studies. Software-predicted Nrf2 binding sites on the thyroglobulin enhancer were validated by site-directed in vitro mutagenesis and chromatin immunoprecipitation.

RESULTS

The study shows that Nrf2 mediates antioxidant transcriptional responses in thyroid cells and protects the thyroid from oxidation induced by iodide overload. Surprisingly, it was also found that Nrf2 has a dramatic impact on both the basal abundance and the thyrotropin-inducible intrathyroidal abundance of thyroglobulin (Tg), the precursor protein of thyroid hormones. This effect is mediated by cell-autonomous regulation of Tg gene expression by Nrf2 via its direct binding to two evolutionarily conserved antioxidant response elements in an upstream enhancer. Yet, despite upregulating Tg levels, Nrf2 limits Tg iodination both under basal conditions and in response to excess iodide.

CONCLUSIONS

Nrf2 exerts pleiotropic roles in the thyroid gland to couple cell stress defense mechanisms to iodide metabolism and the thyroid hormone synthesis machinery, both under basal conditions and in response to excess iodide.

Enhanced Uptake of Iodide from Solutions by Hollow Cu-Based Adsorbents

Cu₂O exhibits excellent adsorption performance for the removal of I⁻ anions from solutions by doping of metallic Ag or Cu. However, the adsorption process only appears on the surface of adsorbents. To further improve the utilization efficiencies of Cu content of adsorbents in the uptake process of I⁻ anions, hollow spheres of metallic Cu, Cu/Cu₂O composite and pure Cu₂O were prepared by a facile solvothermal method. Samples were characterized and employed for the uptake of I⁻ anions under various experimental conditions. The results show that Cu content can be tuned by adjusting reaction time. After the core was hollowed out, the uptake capacity of the samples increased sharply, and was proportional to the Cu content. Moreover, the optimal uptake was reached within only few hours. Furthermore, the uptake mechanism is proposed by characterization and analysis of the composites after uptake. Cu-based adsorbents have higher uptake performance when solutions are exposed to air, which further verified the proposed uptake mechanism. Finally, hollow Cu-based adsorbents exhibit excellent selectivity for I⁻ anions in the presence of large concentrations of competitive anions, such as Cl⁻, SO₄²⁻ and NO₃⁻, and function well in an acidic or neutral environment. Therefore, this study is expected to promote the development of Cu-based adsorbents into a highly efficient adsorbent for the removal of iodide from solutions.

Synthesis and crystal structures of 2-bromo-1,3-di-methyl-imidazolium iodides

Attempts at direct bromination of 1,3-di-methyl-imidazolium salts were futile. The title compounds, 2-bromo-1,3-di-methyl-imidazolium iodide chloro-form 0.33-solvate, C5H8BrN2+·I-·0.33CHCl3, 2-bromo-1,3-di-methyl-imidazolium iodide di-chloro-methane hemisolvate, C5H8BrN2+·I-·0.5CH2Cl2, and 2-bromo-1,3-di-methyl-imidazolium iodide hemi(diiodide), C5H8BrN2+·I-·0.5I2, were obtained by methyl-ation of 2-bromo-1-methyl-imidazole. They crystallized as CHCl3, CH2Cl2 or I2 solvates/adducts. The Br atom acts as a σ-hole to accept short C-Br⋯I inter-actions. C-H⋯I hydrogen bonds are observed in each structure.

Manipulating Band Structure through Reconstruction of Binary Metal Sulfide for High-Performance Thermoelectrics in Solution-Synthesized Nanostructured Bi13 S18 I2

Reconstructing canonical binary compounds by inserting a third agent can significantly modify their electronic and phonon structures. Therefore, it has inspired the semiconductor communities in various fields. Introducing this paradigm will potentially revolutionize thermoelectrics as well. Using a solution synthesis, Bi₂ S₃ was rebuilt by adding disordered Bi and weakly bonded I. These new structural motifs and the altered crystal symmetry induce prominent changes in electrical and thermal transport, resulting in a great enhancement of the figure of merit. The as-obtained nanostructured Bi₁₃ S₁₈ I₂ is the first non-toxic, cost-efficient, and solution-processable n-type material with z T=1.0.

Chemiluminescence detection of trace iodide with flow injection analysis of KMnO4 -carbon dots system

Ultra-weak chemiluminescence (CL) from the reaction of iodide and KMnO₄ was strongly enhanced by carbon nanodots (CNDs) in an acidic medium. The CL intensity was directly proportional to the concentration of iodide in the solution. Therefore, a flow-injection CL system with high sensitivity, selectivity and reproducibility is proposed for the determination of iodide. The proposed method exhibited advantages over a linear range of 3.0 × 10^-6 -1.0 × 10^-4  mol/L and had a detection limit of 3.5 × 10^-7  mol/L. The method was successfully applied to the evaluation of iodide in food samples with recoveries of between 96 and 103%. The relative standard deviations were 2.1 and 4.1% for intra- and inter-assay precision, respectively.