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Dietary intake and urinary excretion of monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine (AsB) were measured in 150 adult Japanese subjects. Duplicate diet (DD) samples and first void of urine on the next morning of DD sampling day were collected and analysed for arsenic species with liquid chromatography-ICP mass spectrometry. Median (min-max) intakes of MMA, DMA and AsB were <2.3 (<2.3-<2.3), 4.57 (<2.3–24.3), and 13.6 (<2.4–231) μg As/day, respectively, and median urinary concentrations were 1.90 (<0.37–26.), 21.9 (<0.27–141) and 19.6 (<0.37–1063) ng As/mg creatinine, respectively. Interrelationships between intake levels and urinary concentrations were mostly significant with positive coefficients indicating mutual association due to co-exposure, metabolism and/or dietary habit. Urinary concentrations and intake levels of AsB were also positively correlated confirming the applicability of urine analysis as biomarker of exposure. The present descriptive results provide with essential piece of information in assessing health risk of methylated arsenicals for population who consume marine products and rice. [ABSTRACT FROM AUTHOR]

Arsenic (As) pollution can lead to an element imbalance in rice. A hydroponic study was carried out to examine the influence of inorganic (arsenate) and organic (dimethylarsinic acid (DMA)) arsenic compounds on the concentration and distribution of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), nickel (Ni), carbon (C), nitrogen (N), and sulfur (S) in rice caryopsis at maturity using laser confocal microscopy and synchrotron X-ray fluorescence (SXRF). Results showed that treatments with inorganic (iAs) and organic (DMA) arsenic did not change the distribution characteristics of the above elements in rice grains. Fe, Mn, and iAs were mainly limited to the ventral ovular vascular trace, while Cu, Zn, and DMA extended into the endosperm. This implies that milling processes are likely to remove a majority of Fe, Mn, and iAs, but not Cu, Zn, and DMA. With regard to the average fluorescent intensity of the rice endosperm, iAs exposure caused significant reductions in Mn (53%), Fe (40%), Cu (27%), and Zn (74%) while DMA treatments decreased Mn (49%), Fe (37%), and Zn (21%). Compared with DMA, iAs exerted more influence on the reduction of these elements in rice caryopsis. In addition, the elemental analysis revealed a significant 12.7% increase for N and 8% reduction for S in DMA-treated rice caryopsis while a significant decrease of 24.0% for S in iAs-exposed rice caryopsis. These findings suggest that Cu, Zn, and S are more easily impacted by iAs, while N is mostly affected by DMA. [ABSTRACT FROM AUTHOR]

Long‐term arsenic exposure can promote cancer through epigenetic mechanisms, and arsenite methyltransferase (AS3MT) plays an important role in this process. However, the expression patterns and mechanisms of AS3MT in arsenic carcinogenesis remain unclear. In this study, we found that the AS3MT was overexpressed in arsenic exposed population, non‐small cell lung cancer (NSCLC) tissues, and A549 cells with sodium arsenite (NaAsO2) treatment for 48 hours. Besides, the level of AS3MT expression was positively correlated with the concentrations of urinary total arsenic (tAs), inorganic arsenic (iAs), methanearsonic acid (MMA), and dimethylarsinic acid (DMA) in all subjects. Functional experiments demonstrated that siRNA‐mediated knockdown of AS3MT significantly inhibited proliferation of A549 cells. Mechanism investigation revealed that silencing of AS3MT inhibited proliferation by increasing mRNA expression levels of p21 and E2F1, and inhibiting CDK1, CDK2, CDK4, CDK6, Cyclin A2, Cyclin E1, Cyclin E2, and PCNA mRNA expression. Therefore, arsenic increased AS3MT expression in vivo and in vitro, which could directly act on the cell and affect the progression of NSCLC by regulating cell cycle genes. [ABSTRACT FROM AUTHOR]

Background: The importance of recognizing and quantifying chemical anions/cations found in various types of samples, including environmental and biological samples, has been extensively studied. Recent findings suggest the possibility of health risks caused by organic compound dimethylarsinic acid (DMAs) rather than its inorganic arsenic metabolite. Objective: This article aims to fabricate polymeric-membrane electrochemical sensors with high sensitivity and selectivity for the cacodylic acid sodium salt dimethylarsinate (DMAs) based on silver diethyldithiocarbamate (AgDDTC) and CuIIphthalocyanine (CuPC) as novel neutral carriers and their applications. Method: DMAs calibration relations and titrations were carried out using a potentiometric workstation equipped with a double-junction reference electrode, in conjunction with the fabricated working electrodes. Results: Sensors revealed fast and stable anionic response with near-Nernstian slopes (–38.660.9 and –31.560.6mV/decade), within concentration ranges (1.7×10–5 –1.0×10–2 and 3.0×10–5 –1.0×10–2 M) and detection limits (1.0×10–5 and 1.6×10–5 M) for AgDDTC- and CuPC-based sensors, respectively. Sensors are characterized by extended life-time, signal stability, high precision and short response times. Selectivity for the cacodylate anion over most common anions was tested for the proposed electrodes. Sensors were satisfactorily applied for DMAs quantification in biological matrices with recoveries ranging between 96.2 and 99.0%. Membrane sensors were interfaced with a flow-through system for continuous monitoring of DMAs. The sensors were tested for the assay of different amino acids based on their reaction with cacodylate, where reaction end points were monitored with the proposed electrodes using direct potentiometric determination and flow injection analysis (FIA). Conclusions : Potentiometric ion-selective PVC-membrane electrodes based on silver diethyldithiocarbamate (AgDDTC) and CuIIphthalothyanine (CuPC) provide adequate and reliable means for the determination of dimethylarsenate anion (cacodylate anion, DMAs). These membrane electrodes are easy to manufacture, they have the advantages of high selectivity and sensitivity, broad dynamic ranges, low detection limits, quick response times and cost effectiveness. Such properties make these sensors suitable for the assay of DMAs levels in aqueous solutions by direct potentiometry, flow injection and potentiometric titration, as well as in monitoring of the titration end points of the reactions between various amino acids and DMAs anion in aqueous solutions. Highlights: Simple electrochemical membranes for dimethylarsinate (DMAs) were prepared, based on diethyldithiocarbamate (AgDDTC) and CuIIphthalocyanine (CuPC). - DMAs sensors were fabricated in two different modules: batch (for static) and flow-through (for hydrodynamic) approaches. - Levels of DMAs were determined in spiked biological samples. - AgDDTC-based sensors were successfully applied in the determination of several amino acids via potentiometric titration with DMAs. [ABSTRACT FROM AUTHOR]

Arsenic is a wildly distributed carcinogen in the environment. Arsenic-induced apoptosis has been extensively studied in therapeutics and toxicology. LncRNA MEG3 has been extensively studied as apoptosis regulatory gene in recent years. However, it stays unclear regarding how the mechanism of MEG3 regulates arsenic-induced apoptosis. Our focus was to explore the effects of MEG3 on arsenic-induced apoptosis. MTS assay was used to test cell viability, and qRT-PCR was for the examination of gene expressions. The effect of the apoptosis and necrosis after knockdown MEG3 was detected with double staining. Our results demonstrated that MEG3 expression was positively correlated with the concentration of three arsenic species (inorganic arsenic (iAs), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)) (p < 0.05). The ability of iAs to induce MEG3 expression was much higher compared with that induced by MMA and DMA. In addition, our experiments confirmed that MEG3 knockdown increased cell viability and arsenic-induced apoptosis, but cell viability decreased after iAs treatment. Moreover, LncRNA MEG3 regulated apoptosis via down-regulate API5 while up-regulate CASP7, CCND3 and APAF1. It is further proved that arsenic-induced apoptosis increased after the knockdown of MEG3, which regulates these genes. These findings provide experimental evidence and possible mechanisms for subsequent research on the effects of arsenic on health. [ABSTRACT FROM AUTHOR]

Arsenic can accumulate in freshwater biota, sometimes reaching potentially harmful levels. However, the toxicity of arsenic strongly depends on which arsenic species are present. Although organic species are considered less harmful than inorganic ones, they have not been extensively studied in freshwater environments, and drivers of variation in arsenic speciation among sites and taxa remain unclear. We assessed concentrations of two organic arsenic species, arsenobetaine (AsB) and dimethylarsinic acid (DMA), in fish and invertebrates from three lakes near Sudbury, Ontario, Canada-a region with widespread mining impacts. Both AsB and DMA were detected in most samples (n = 212), varying across a wide range of concentrations (<0.001-30.144 and <0.006-5.262 mg/kg dry wt, respectively). The lake with the most severe mining impacts typically had the highest concentrations (designated by square brackets []) of AsB and DMA. In contrast, the percentage of total arsenic made up by AsB (%AsB) and DMA (%DMA) did not vary significantly between lakes. Arsenic speciation in fish muscle varied with fish size, selenium concentrations, and trophic elevation (inferred from nitrogen stable isotope ratios δ 15 N), but relationships with dietary carbon source (inferred from carbon stable isotope ratios δ 13 C) were more varied. Within all three lake food webs, [AsB] and [DMA] typically underwent biodilution, decreasing with trophic elevation (i.e., δ 15 N). Although the aforementioned factors explained some variation in arsenic speciation, there remains considerable unexplained variation. Further studies on arsenic speciation in freshwater biota should target a wider diversity of taxa to better understand drivers of variation in arsenic speciation. In addition, research emphasizing the percentage of inorganic arsenic and other organic arsenic species is needed to improve environmental and human health risk assessments. Environ Toxicol Chem 2024;43:833-846. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Thioarsenates have recently been detected in rice and rice-based products, with particularly high contents in puffed rice cakes. Here, we show that puffing rice can cause almost complete transformation of dimethylarsenate (DMA) to dimethyldithioarsenate (DMDTA) and dimethylmonothioarsenate (DMMTA). Analysis of puffed rice cakes after 3 months of non-sealed storage at room temperature showed transformation of DMDTA mainly into DMMTA. From a food safety perspective, this likely represents an increased risk because DMMTA is highly cytotoxic and misidentified as non-regulated DMA by routine acid extractions. Analysis of 80 commercial puffed rice cakes confirmed widespread occurrence of thioarsenates. The sum of non-regulated, but potentially toxic DMMTA and DMDTA reached values up to 537 µg·kg -1 and 241 µg·kg -1 for generic and infant-labeled rice cakes, respectively. Our results highlight the importance of better understanding (de)thiolation processes along the rice cake-production chain and potentially revising current thresholds set for iAs to include DMMTA and DMDTA., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

BackgroundIn humans, inorganic arsenic (iAs) is metabolized to methylated arsenical species in a multistep process mainly mediated by arsenic (+3 oxidation state) methyltransferase (AS3MT). Among these metabolites is monomethylarsonous acid (MMAIII), the most toxic arsenic species. A recent study in As3mt-knockout mice suggests that unidentified methyltransferases could be involved in alternative iAs methylation pathways. We found that yeast deletion mutants lacking MTQ2 were highly resistant to iAs exposure. The human ortholog of the yeast MTQ2 is N-6 adenine-specific DNA methyltransferase 1 (N6AMT1), encoding a putative methyltransferase.ObjectiveWe investigated the potential role of N6AMT1 in arsenic-induced toxicity.MethodsWe measured and compared the cytotoxicity induced by arsenicals and their metabolic profiles using inductively coupled plasma-mass spectrometry in UROtsa human urothelial cells with enhanced N6AMT1 expression and UROtsa vector control cells treated with different concentrations of either iAsIII or MMAIII.ResultsN6AMT1 was able to convert MMAIII to the less toxic dimethylarsonic acid (DMA) when overexpressed in UROtsa cells. The enhanced expression of N6AMT1 in UROtsa cells decreased cytotoxicity of both iAsIII and MMAIII. Moreover, N6AMT1 is expressed in many human tissues at variable levels, although at levels lower than those of AS3MT, supporting a potential participation in arsenic metabolism in vivo.ConclusionsConsidering that MMAIII is the most toxic arsenical, our data suggest that N6AMT1 has a significant role in determining susceptibility to arsenic toxicity and carcinogenicity because of its specific activity in methylating MMAIII to DMA and other unknown mechanisms.

Arsenic is a ubiquitous, toxic element that is efficiently accumulated by rice plants. This study assessed the spatial variability in the total As (tAs) contents and organic and inorganic forms in different types of rice, plant parts (husk, stem, leaves and phytoliths) and residues. Samples were collected in different countries in Latin America (Ecuador, Brazil and Peru) and the Iberian Peninsula (Spain and Portugal). The tAs content in commercial polished rice from the Latin American countries was similar (0.130–0.166 mg kg−1) and significantly lower than in the rice from the Iberian countries (0.191 ± 0.066 mg kg−1), and together, the tAs concentration in brown rice (236 ± 0.093 mg kg−1) was significantly higher than in polished and parboiled rice. The inorganic As (iAs) content in rice was similar in both geographical regions, and the aforementioned difference was attributed to dimethylarsinic acid (DMA). The relative abundance of organic species increased as the tAs content in rice grain increased. A meta-analysis of our and previously reported data confirmed the negative correlation between iAs/tAs and tAs. At low tAs concentrations, inorganic forms are dominant, while at higher values (tAs > 0.300 mg kg−1) the concentration of organic As increases substantially and DMA becomes the dominant form in rice grain. On the contrary, inorganic arsenic was always the dominant form, mainly as arsenate [As(V)], in leaves and stems. The presence in soils of high concentrations of amorphous Fe and Al oxides and hydroxides, which are capable of strongly adsorbing oxyanions (i.e. arsenate), was associated with low concentrations of As in rice plants. In addition, the presence of high concentrations of As(V) in stems and leaves, low concentration of As in phytoliths, and the As associated with organic matter in stems and husk, together suggest that rice plants take up more As(V) than As(III). [ABSTRACT FROM AUTHOR]

Straighthead disease is a physiological disorder in rice with symptoms of sterile spikelets, distorted husks, and erect panicles. Methylated arsenic species have been implicated as the causal agent of the disease, but direct evidence is lacking. Here, we investigated whether dimethylarsinic acid (DMA) causes straighthead disease and its effect on the transcriptome of young panicles. DMA addition caused typical straighthead symptoms in hydroponic culture, which were alleviated by silicon addition. DMA addition to soil at the tillering to flowering stages induced straighthead disease. Transgenic rice expressing a bacterial arsenite methyltransferase gene gained the ability to methylate arsenic to mainly DMA, with the consequence of inducing straighthead disease. Field surveys showed that seed setting rate decreased with increasing DMA concentration in the husk, with an EC50 of 0.18 mg kg−1. Transcriptomic analysis showed that 364 and 856 genes were significantly up- and down-regulated, respectively, in the young panicles of DMA-treated plants compared with control, whereas Si addition markedly reduced the number of genes affected. Among the differentially expressed genes, genes related to cell wall modification and oxidative stress responses were the most prominent, suggesting that cell wall metabolism is a sensitive target of DMA toxicity and silicon protects against this toxicity. [ABSTRACT FROM AUTHOR]

With recently legislated maximum levels of inorganic arsenic (iAs) in white and brown rice in Canada, the regulatory bodies are evaluating the need for regulation of As levels in infant food products. Rice is a major part of infants' diet, and therefore, the presence of As in this staple food causes concerns. So far, the scientific community was lacking suitable certified reference material (CRM) which could be used to assess the accuracy of developed analytical methods for As speciation in infants' food products. As a result, we have developed BARI-1, a baby cereal coarse rice flour reference material which was certified for total arsenic (0.248 ± 0.018 mg kg−1), cadmium (0.0134 ± 0.0014 mg kg−1), mercury (0.0026 ± 0.0003 mg kg−1), lead (0.0064 ± 0.0016 mg kg−1), inorganic As (0.113 ± 0.016 mg kg−1) and dimethylarsinic acid (DMA) (0.115 ± 0.010 mg kg−1), and reference value for monomethylarsonic acid (MMA) (0.0045 ± 0.0008 mg kg−1) was reported. We also observed trace amounts of an unknown As compound, with chromatographic retention time close to DMA. Participating laboratories were allowed to use their in-house-validated extraction and/or digestion methods, and the detection of total metals was done by ICP-MS whereas HPLC-ICP-MS was used for As speciation. Despite the diversity in sample preparation and quantitation methods, reported values were in good agreement. For iAs measurement, the comparison between hydride generation ICP-MS and HPLC-ICP-MS found iAs overestimation with the former method, possibly due to interference from DMA. The certification was accomplished with a CRM rapid response approach in collaborative, focused effort completing the CRM development in few months instead of the typical multiyear project. This approach allowed to respond to measurement needs in a timely fashion. [ABSTRACT FROM AUTHOR]

Since arsenic (As) exposure is largely due to geochemical contamination, this study focused on the remediated area of Santana do Morro, a district of Santa Bárbara, Minas Gerais, Brazil, which was previously contaminated with As due to gold mining. Total As concentrations in sediment, soil and plants were determined, next to As species, anionic arsenic compounds As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), in plants samples. Total As concentrations in soil and sediments were slightly elevated (16-18 µg g-1) and most of the plants contained low levels of As (< 1 µg g-1). The exception was a native plant Eleocharis geniculata (L.) which contained elevated levels of As (4 µg g-1). The exposure of this plant to As under controlled conditions (hydroponics) indicated its possible tolerance to elevated As levels and suggesting its potential use in phytomonitoring of As-contaminated sites. This plant is able to metabolize arsenate to arsenite and contained MMA and DMA, both in its natural habitat and under controlled conditions. [ABSTRACT FROM AUTHOR]

In the absence of adequate molecular oxygen in a continuously flooded soil, other oxidizing anions can potentially oxidize arsenite (As(III)) into arsenate (As(V)) and reduce the bioavailability of arsenic (As) to rice while maintaining high rice yield. We conducted a greenhouse study to evaluate the effect of two prevalent oxyanions (10 mg/L nitrate and/or 50 μg/L perchlorate) on the As uptake, speciation, and accumulation in a hybrid rice (XL753) at the heading and maturity stages. The presence of nitrate and/or perchlorate at the used concentrations increased the rice grain yield by 35–93% to16.6–23.8 g/pot while lowering the total As in rice grains by 34–45% to 0.81–0.97 mg/kg dry weight. Perchlorate alone led to the greatest decrease in total As. Organic As was the predominant species in rice grains, with dimethylarsinic acid (DMA) accounting for 66–76% of total As in all treatments. In contrast, inorganic As was the dominant As form in rice straws and roots, with As(V) accounting for 62.4–91.4% of total As in all treatments. The translocation and accumulation of different As species in rice tissues varied at different growth stages in the presence of two tested oxyanions, as indicated by the ratios of inorganic vs organic As and inorganic As(III) vs As(V). Overall, the presence of oxyanions in irrigation water at the tested concentrations significantly decreased the total As accumulation in rice grains, while enhancing the rice yield. [ABSTRACT FROM AUTHOR]

Background: Detoxification of inorganic arsenic (iAs) occurs when it methylates to form monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Lower proportions of urinary iAs and MMA, and higher proportions of DMA indicate efficient methylation. The role of B-vitamins in iAs methylation in children with low-level arsenic exposure is understudied.Objectives: Our study objective was to assess the association between B-vitamin intake and iAs methylation in children with low-level arsenic exposure (<50 µg/L in water; urinary arsenic 5-50 µg/L).Methods: We conducted a cross-sectional study in 290 ∼7-y-old children in Montevideo. Intake of thiamin, riboflavin, niacin, vitamin B-6, and vitamin B-12 was calculated by averaging 2 nonconsecutive 24-h recalls. Total urinary arsenic concentration was measured as the sum of urinary iAs, MMA, and DMA, and adjusted for urinary specific gravity; iAs methylation was measured as urinary percentage As, percentage MMA, and percentage DMA. Arsenic concentrations from household water sources were assessed. Linear regressions tested the relationships between individual energy-adjusted B-vitamins and iAs methylation.Results: Median (range) arsenic concentrations in urine and water were 9.9 (2.2-48.7) and 0.45 (0.1-18.9) µg/L, respectively. The median (range) of urinary percentage iAs, percentage MMA, and percentage DMA was 10.6% (0.0-33.8), 9.7% (2.6-24.8), and 79.1% (58.5-95.4), respectively. The median (range) intake levels of thiamin, riboflavin, niacin, and vitamin B-6 were 0.81 (0.19-2.56), 1.0 (0.30-2.24), 8.6 (3.5-23.3), and 0.67 (0.25-1.73) mg/1000 kcal, respectively, whereas those of folate and vitamin B-12 were 216 (75-466) and 1.7 (0.34-8.3) µg/1000 kcal, respectively. Vitamin B-6 intake was inversely associated with urinary percentage MMA (β = -1.60; 95% CI: -3.07, -0.15). No other statistically significant associations were observed.Conclusions: Although vitamin B-6 intake was inversely associated with urinary percentage MMA, our findings suggest limited support for a relation between B-vitamin intake and iAs methylation in children exposed to low-level arsenic. [ABSTRACT FROM AUTHOR]

Much attention has been paid to the pollutant dimethylarsenic acid (DMA), because of its high toxicity even at very low doses. Although TiO 2 photocatalytic oxidation (PCO) is one of the few effective methods for treating DMA-containing water, the efficient decomposition of DMA and simultaneous removal of toxic arsenic species remains a significant but challenging task. Here, defective mesoporous TiO 2 with mixed-phase structure was synthesized and used as both photocatalyst and adsorbent for DMA removal. Due to the reduced band-gap and enhanced separation of photogenerated charge carriers, the oxygen-deficient TiO 2 nanostructures exhibited 4.2 times higher PCO efficiency than commercial TiO 2 (P25). More importantly, the high surface area of the mesoporous TiO 2 provided sufficient active sites for in-situ adsorption and reaction, resulting in the efficient removal of as-formed As(V). Combining the experimental and characterization results, the different roles of reactive species during PCO reactions were clarified. In the presence of hole (h+) as the dominant oxidation species, DMA was demethylated and transformed into MMA. Thereafter, MMA was subsequently reduced to As(III) by photo-generated electrons. Superoxide radicals (O 2 •–) played a significant role in oxidizing As(III) into As(V), which was finally adsorptively removed by the mesoporous TiO 2. Image 1 [ABSTRACT FROM AUTHOR]

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Two field experiments were carried out in a private farm under drip irrigation with fertigation system at Kafr El-Sheik Governorate, during summer seasons of 2018 and 2019 in order to study the effect of organic compounds like algae extract freely(at a rate of 4,3, 2 L/Fed. for 3 times and control ) and chemical treatments application like K,Ca compounds (at a rate of 4 L/Fed. for 3 times) and the interaction between them (at half amount of each one for 3 times) to minimize the harmful of salinity compared with control on vegetative growth characters, leaf pigments, yield and yield components, fruit quality and leaf chemical constituents of sweet pepper plants (Capsicum annuum L.). cv. Spanish pepper. Vegetative growth characters, i.e. plant hight, number of branches, leaf number, dry weight / plant, leaf area /plant, fruit yield and its components parameters and TSS in fruit juice were significantly decreased by decaling the amount of algae extract freely in the irrigation water from 4 L/Fed. (3 times) to control (without addition of algae extract freely), while treats with 4L/Fed. gave the highest values of K percentage on fruit. On the other hand, control treatments resulted in the highest values of titratable acidity and proline contents in the leaves. Sweet pepper plants were treated with the combination of K chemical compounds at 2L/Fed. and Ca chemical compounds at 2 L/Fed. for 3 times recorded the highest values of all studied growth characters, average fruit weight, early yield, total yield, TSS and nitrogen percentage followed by Ca chemical compound at 4L/Fed. with non-significant differences between both treatments. While, plants were received K chemical compound at 4 L/Fed. was recorded the highest values of phosphorus percentage. Algae extract freely at a rate of 4 L/Fed. in combination with k chemical compound at a rate of 4 L/Fed. separately or with Ca chemical compound at 4 L/Fed. caused a stimulatory effect on most of the studied characters of sweet pepper plants. Meanwhile, the same treatments were recorded the lowest values of TSS in fruits of sweet pepper. On the other hand, the control plants without either algae extract freely or K and Ca compounds recorded the lowest values of all studied growth characters, yield and its components and fruit quality as effects of salinity. Economically, it is inferred that using of algae extract freely at a rate of 4L/Fed. plus potassium chemical compound at a rate of 4L/Fed. could be recommended for increasing unit productivity and also net profit, in addition of high quality of pepper fruits. [ABSTRACT FROM AUTHOR]

An ion-exchange resin Lewatit FO 36 was used for the preparation of a new resin gel for the diffusive gradient in thin films technique (DGT). The DGT method was optimized for the accumulation of four bioavailable arsenic species (AsIII, AsV, monomethylarsonic acid, dimethylarsinic acid) in the aquatic environment. The total sorption capacity of Lewatit FO 36 resin gel was 535 μg As disc−1. The microwave-assisted extraction in the presence of NaCl (10 g L−1) and NaOH (10 g L−1) was used for the isolation of arsenic species from the Lewatit FO 36 resin gel. The elution efficiency of arsenic was 98.4 ± 2.0%. Arsenic was determined by the optimized electrothermal atomic absorption spectrometry (ET-AAS) method using palladium modifier, pre-atomization cool-down step and tungsten carbides coating of graphite tube. The Lewatit FO 36 resin gel provides accurate results (c DGT /c SOL ratio 0.86–1.00) in the pH range 4–8. No significant influence of experimental conditions was observed in the presence of chlorides (0–0.5 mol L−1) and humic acid (0–100 mg L−1). Only a very high concentration of phosphates (10 mg L−1) caused a slight decrease in the diffusion coefficients of MMA and AsV species (8.4% and 12.4%, respectively). The presence of iron (0–1 mg L−1) caused a decrease in the diffusion coefficients, but with regard to the common concentrations of iron (less than 0.3 mg L−1), the negative effect was considered not significant for AsIII and DMA in natural water. The DGT-ET-AAS method was applied for the determination of bioavailable arsenic species in the spiked river water samples and also in-situ in the water reservoir. The new resin gel was characterized by a homogeneous gel structure with excellent reproducibility (< 5% variation of results between batches) and high sorption capacity which suggests its possible long-term application (up to 286 days in the environment with the arsenic concentration of 100 μg L−1). Image 1 • New DGT resin gel utilizing Lewatit® FO 36 resin was developed. • High total sorption capacity of four arsenic species (AsIII, AsV, MMA, DMA). • Influence of various external factors (pH, iron, chlorides, humic acid, phosphates) was tested. • Evaluation of DGT method on real samples (in labortory and in-situ). [ABSTRACT FROM AUTHOR]

Pregnant CD-1 mice received 200 ppm dimethylarsinic acid (DMA) in the drinking water from gestation day 8–18, and tumor formation was assessed in offspring at the age of 84 weeks. DMA elevated the incidence of lung adenocarcinoma (10.0%) and total tumors (33.3%) in male offspring compared to male control offspring (1.9 and 15.1%, respectively). DMA also elevated the incidence of hepatocellular carcinoma (10.0%) in male offspring compared to male control offspring (0.0%). DMA and its metabolites were detected in the lungs of transplacental DMA-treated neonatal mice. Transplacental DMA exposure increased cell proliferation in the epithelium in the lungs of both neonatal and 6-week-old male mice. Microarray and real-time PCR analyses detected high expression of keratin 8 (Krt8) in the lungs of both neonatal and 6-week-old DMA-treated mice. Western blot analysis indicated that DMA elevated methylation of histone H3K9, but not H3K27, in the lungs of male mice. Importantly, chromatin immunoprecipitation sequencing (ChIP-seq) analysis using an H3K9me3 antibody found differences in heterochromatin formation between mice exposed to DMA and the controls. Notably, ChIP-seq analysis also found regions of lower heterochromatin formation in DMA-treated mice, and one of these regions contained the Krt8 gene, agreeing with the results obtained by microarray analysis. High expression of Krt8 was also detected in adenoma and adenocarcinoma of the lung in male offspring. Overall, these data indicate that transplacental DMA treatment enhanced lung and liver carcinogenesis in male mice. In the lung, DMA caused aberrant methylation of histone H3K9, increased Krt8 expression, and enhanced cell proliferation. [ABSTRACT FROM AUTHOR]

Aims: Dimethylarsinic acid (DMA), an organic arsenic compound found in rice grain, is a causal agent of straighthead disorder, which can decimate yields. To minimize rice accumulation of DMA, we tested 9 molecules for antagonistic effects with DMA. We also tested whether the source of nitrogen is able to affect DMA uptake, as DMA is a weak acid and different nitrogen sources have differing effects on rhizospheric pH. Methods: We grew rice (Oryza sativa L. cv. Lemont) hydroponically to maturity in two different experiments. First, 9 potential competitors (boric acid, calcium, glycerol, glycine, lactic acid, phosphoric acid, serine, silicic acid, and urea) were included in the hydroponic solution at a molar ratio ≥ 100:1 competitor:DMA. Second, rice receiving 5 μM DMA was grown under ammonium, nitrate, or a 1:1 mix of ammonium and nitrate. Yield metrics and plant elemental concentrations were measured after harvest. Results: Of the potential competitors, only silicic acid was able to alleviate straighthead disorder and no competitors were able to reduce grain As by ≥30%. Under differing nitrogen sources, nitrate decreased plant concentrations of As relative to ammonium, but not in the grain. Conclusions: While Si can alleviate DMA uptake, there remains uncertainty in how most DMA enters the plant. [ABSTRACT FROM AUTHOR]

Carbonic anhydrase modification (chemical and biological) is an attractive strategy for its diverse application to accelerate the absorption of CO2 from a flue gas with improved activity and stability. This article reports various possibilities of CA modification using metal–ligand homologous chemistry, cross-linking agents, and residue- and group-specific and genetic modifications, and assesses their role in carbon management. Chemically modified carbonic anhydrase is able to improve the absorption of carbon dioxide from a gas stream into mediation compounds with enhanced sequestration and mineral formation. Genetically modified CA polypeptide can also increase carbon dioxide conversion. Chemical modification of CA can be categorized in terms of (i) residue-specific modification (involves protein–ligand interaction in terms of substitution/addition) and group-specific modifications (based on the functional groups of the target CA). For every sustainable change, there should be no/limited toxic or immunological response. In this review, several CA modification pathways and biocompatibility rules are proposed as a theoretical support for emerging research in this area. [ABSTRACT FROM AUTHOR]

A study on the transformations of six arsenic species (arsenocholine (AsC), arsenobetaine (AsB), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenite (As(III)), and arsenate (As(V))) was carried out in aqueous solution by ultrasonic treatment. The transformations of arsenic species increased with time. As the ultrasonic power or temperature was increased, transformations of arsenic species were at first enhanced and then decreased. AsC, AsB, As(III) were the most unstable at 600 W and 20 °C. DMA and MMA were stable; AsC was partially transformed to AsB, trimethylarsinic oxide (TMAO), and the more toxic tetramethylarsonium ion (TMA+); AsB was partially transformed to TMAO; and As(III) was easily oxidized to As(V). The reduction of As(V) to As(III) was only observed when the temperature was over 60 °C. The ultrasound treatment conditions with relatively stable arsenic species were 150 to 300 W, 40 to 80 °C, and 0 to 10 min. The relatively stable (150 W, 10 min, 80 °C) and unstable (600 W, 60 min, 20 °C) ultrasonic condition were applied to mushrooms and the transformations of AsC, AsB, and As(III) were observed. Currently, ultrasound-assisted extraction methods have only focused on the extraction efficiency of arsenic species and ignored their transformations. This study may serve as a guide for improving extraction efficiency without minimal transformation of the arsenic forms to reflect the actual contents in edible mushrooms. The study also provides a theoretical basis for making an accurate risk evaluation of human exposure by taking account of possible arsenic transformations during processing prior to consumption. [ABSTRACT FROM AUTHOR]

A dual column packed with a magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) in microfluidic chip channels is described for array chip-based magnetic solid phase microextraction of arsenic species including arsenite [As(III)], arsenate [As(V)], monomethylarsonous acid (MMA) and dimethylarsinic acid (DMA) in SCC-7 cells. At pH 6, the MFC-SH adsorbs As(III) while MFC quantitatively adsorbs As(V), DMA and MMA. The As(III) adsorbed on the MFC-SH can be desorbed with a 2% solution of thiourea in 0.5 M HNO3. The arsenic species MMA, DMA and As(V) are retained on the MFC but can be desorbed by ammonia. A sequential elution strategy was employed to elute MMA, DMA, As(V) and As(III) one by one for subsequent on-line determination by ICP-MS. The limits of detection are 4.8, 6.3, 3.8 and 7.1 ng L−1 for As(V), DMA, MMA and As(III), respectively. The enrichment factors are between 23 and 25, and the throughput is 7 samples per hour. The arsenic species in (spiked) SCC-7 cell samples were analyzed by the online system with adequate recoveries (89–110%). [ABSTRACT FROM AUTHOR]

Urinary bladder cancer would be a serious health issue among human individuals. Current treatments are not effective so there is to be an optional therapy should be introduced to halt the reoccurrence of cancer. Phytochemicals does not own any adverse effect in patients with cancer. Our research is to investigate that the Diindolylmethane (DIM) and Lupeol treatment eliminates urinary bladder cancer development by activating the apoptosis by its anti-inflammatory properties. The male albino wistar rats were equally separated into 6 groups. Each group possesses 10 rats. G-I: Control. G-II: N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) was administered orally for 8 weeks. After 8 weeks of BBN toxicity, Dimethylarsinic acid (DMA) was provided for 28 weeks in drinking water. G-III and G-IV: After BBN initiation, DMA was provided for 28 weeks in drinking water. Diindolylmethane and Lupeol were also administered orally for 28 weeks along with DMA. G-V and G-VI: Diindolylmethane alone and Lupeol alone were administered orally for 36 weeks. The experimental rats were euthanized at 36th week. The urinary bladder was macroscopically and microscopically analyzed in control and treated groups. Diindolylmethane and Lupeol therapy inhibited the tumor formation in the urinary bladder. Our study proved that both Diindolylmethane and Lupeol are being capable of targeting these signaling pathways which would make them potentially applicable to cancer chemoprevention and treatment. [ABSTRACT FROM AUTHOR]

A gas chromatography with mass spectrometry was developed for the determination of selected organoarsenic compounds, for example, monomethylarsonic acid, dimethylarsinic acid, phenylarsonic acid, nitarsone and roxarsone, in aquatic environment. For the analysis by gas chromatography, analytes was derivatized with 1,3-propanedithiol. The cyclic dithiaarsenoline formed was extracted from the sample matrix by solid-phase microextraction (SPME). The extraction studies were carried out on different types of extraction fibers such as polyacrylate, polydimethylsiloxane-modified divinylbenzene, carboxenpolydimethylsiloxane, divinylbenzene carboxen polydimethylsiloxane under different conditions. The optimized SPME conditions employed a 65 µm polydimethylsiloxane divinylbenzene fiber, derivatization reaction temperature of 60°C and fiber equilibration time of 30 min. The method allows for the simultaneous determination of monomethylarsonic acid, dimethylarsenic acid, phenylarsonic acid, roxarsone and nitarsone. The repeatability of the analytical method is in the range from 0.78% to 3.23%, and the limits of determination ranging from 0.35 to 5.88 µg L-1, depending on the compound. The method was applied to determine an organoarsenic compounds in mining water and wastewater from metallurgy of non-ferrous metals industry. [ABSTRACT FROM AUTHOR]

A study of epitaxial growth of GaAs islands on (2×1) reconstructed SrTiO3(001) surface is presented. Under low arsenic partial pressures (PAs), GaAs islands are (001)-oriented, and increasing PAs leads to the progressive formation of (111)-oriented GaAs islands. This results from the competition between the formation of Ga-O and Ga-As bonds at the early stages of the growth, as supported by the analysis of the evolution of the island density with respect to PAs. [ABSTRACT FROM AUTHOR]

Growing studies investigated the association of arsenic metabolism with type 2 diabetes (T2D), however, the epidemiological evidence is inconsistent. In addition, the interaction of arsenic metabolism-related genetic risk score (GRS)-arsenic on T2D risk was unclear. The present study aimed to evaluate the association of arsenic metabolism efficiency [inorganic arsenic (iAs)%, monomethylarsonic acid (MMA)%, and dimethylarsinic acid (DMA%)] with T2D risk. Moreover, the relationship of GRS and arsenic metabolism efficiency and the interaction of GRS-arsenic on T2D were investigated. Age- and sex-matched new-onset diabetes case-control study derived from the Dongfeng-Tongji cohort was conducted and 996 pairs participants were included in this study. The leave-one-out approach was used to evaluate the association of arsenic metabolism efficiency with T2D risk. The GRS and weight GRS (wGRS) were calculated based on 79 candidate SNPs. We estimated the relationship of GRS with arsenic metabolism efficiency by linear regression model. The interaction of GRS-arsenic on T2D was assessed by adding a multiplicative interaction term (GRS × arsenic) in the logistic regression models. Urinary iAs% was positively associated with T2D risk, and the OR (95% CI) was 1.06 (1.01, 1.12). MMA% and PMI were negatively associated with T2D risk, and the ORs (95% CI) were 0.87 (0.78, 0.97) and 0.64 (0.47, 0.86), respectively. Urinary DMA, As3+, and As5+ were positively associated with T2D risk. Similar relationships were found between arsenic metabolites and levels of FPG and HbA1c. Moreover, arsenic metabolism-related GRS/wGRS was positively associated with MMA% but negatively associated with DMA%. Genetic predisposition to arsenic metabolism modified the association of inorganic arsenic with T2D risk (P interaction = 0.033). Taken together, lower arsenic primary metabolism efficiency (higher iAs% and lower MMA%) may increase T2D risk. Genetic predisposition to arsenic metabolism was associated with arsenic metabolism efficiency, and might modify the association of inorganic arsenic with T2D risk. [Display omitted] • Higher iAs% and lower MMA% increased the risk of T2D. • Genetic predisposition was associated with arsenic metabolism efficiency. • Genetic predisposition may modify the association of inorganic arsenic with T2D risk. [ABSTRACT FROM AUTHOR]

Dimethylarsinic acid (DMA) is one of the common arsenic (As) species present in soil and is more toxic to plants than others. Identifying the crucial elements for plant growth under DMA stress is essential to enhance plant tolerance to DMA. Herein, we provided for the first time an ionome–based approach to address this issue. The phenotype, As species and concentrations of 11 essential elements in lettuce tissues were monitored under exposures of 0.1, 0.5, 1, 2, 5 mg L−1 DMA in hydroponic culture for 32 days. Lettuces remained normal (no significant difference in phenotype from the control) under 0.1–2 mg L−1 DMA stress, and were inhibited with fresh weights of leaf and root under 5 mg L−1 DMA stress. Integrating the difference in ionome profiles between the two growth states (normal and inhibited) and the responses of the individual element, Mg and S were clarified as the most possible candidates for the crucial elements for lettuce growth under DMA stress. Under 5 mg L−1 DMA stress, the accumulation of Mg and S declined, yet their BCF values were significantly increased, which was consistent with the change in BCF of DMA. Based on the physiological functions of Mg and S and the toxicity of DMA, it could be inferred that the enhanced transfer of Mg and S to leaves should be induced by the potential damage caused by the increased DMA accumulation in leaves, and would result in a shortage of both elements in roots as well as the growth inhibition. [Display omitted] • Applying ionome to identify crucial elements for lettuce growth under DMA stress. • Ionome profiles varied in lettuce growth states. • Mg and S were the crucial elements for lettuce growth under DMA stress. • The transfer of Mg and S to leaves was enhanced when lettuce growth was inhibited. • The transfer of DMA to leaves was enhanced when lettuce growth was inhibited. [ABSTRACT FROM AUTHOR]

This study assessed heavy metal levels (lead (Pb), cadmium (Cd), total arsenic (tAs), arsenite (As (III)), arsenate (As (V)), monomethyl arsenic acid (MMA), dimethylarsinic acid (DMA), total mercury (tHg), and methylmercury (MeHg)) in six organs (total portion, head, body, shell, muscle, and intestine) of 11 shrimp species distributed in Korea. Shrimp exhibited significant variability in heavy metal accumulation, with Alaskan pink and dried shrimp (Lesser glass, Southern rough, and Chinese ditch prawn) showing the highest metal concentrations. Notably, the intestine having the highest overall metal content, while Cd was most prominent in the head, tHg was highest in the muscle. The Hazard Quotient values of 11 shrimp species in South Korea were below the European Food Safety Authority's allowable limits for heavy metals. This study illuminates the heavy metal profiles of distributed shrimp in Korea and emphasizes the ongoing need for monitoring heavy metals on seafood to ensure consumer safety. • The distribution tendency of heavy metals was organ-dependent in shrimp. • Alaskan pink shrimp and dried shrimp exhibit significant accumulation of heavy metals. • Head weight ratio and Cd, tHg, MeHg concentrations in shrimp show a positive correlation. • Dietary exposure to heavy metals via shrimp consumption remains within safe limit for all. [ABSTRACT FROM AUTHOR]

[Display omitted] • Origin of Cl and CA tuned Pd particle shape is revealed by DFT + Wulff construction. • High chemical potential of adsorbate favors the particle formation with same facet. • Adsorbate number per unit area affect surface stability more than adsorption energy. • Adsorbate rigidity/flexibility affects its number per unit area and particle shape. • The insights can guide particle synthesis in desired shape for various application. Capping agents such as halide and citrate (CA) are crucial in the colloidal synthesis of noble metal nanoparticles (NPs) with desirable shape for specific catalytic reaction. Halide ions have been shown to stabilize the cubic NP while CA ions favor the octahedral NP regardless of the noble metals, but the mechanism remains unclear. We combine DFT calculations and Wulff construction to understand how the morphology of Pd particle changes with Cl and CA chemical potential (μ). Three main factors are identified to affect the morphology of Pd particle: μ of adsorbate, its number per unit area (N AS /S), and rigidity or flexibility. Increasing μ of adsorbate or its N AS /S causes decreased surface free energy and increased exposed surface area. Moreover, rigid adsorbates (PdCl x) occupy a larger surface area for surfaces with high atomic density such as Pd(1 1 1), leading to cubic Pd particle at high μ Cl. Conversely, flexible adsorbates (CA) that can adjust their structure based on the surface occupy smaller surface area on Pd(1 1 1), favoring octahedral Pd particle. This work reveals the origin for capping agent tuned morphology of Pd NP, and the insights can be used to guide metal NP synthesis with desired morphology for catalytic reactions of technological interest. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced carbon aerogel (C/CA) composites are promising candidates for thermal protection at ultra-high temperatures. However, the poor anti-oxidative performance and difficulties in preparing a dense and crack-free coating without damaging the substrate have limited their use in oxidizing environments. Here, we have prepared a dense SiC coating on C/CA by chemical vapor deposition under the assistance of a SiC gradient layer derived from in-situ ceramization of the CA matrix. By courtesy of the gradual compaction and composition, the SiC bilayer coating with 440 μm thickness is crack-free and has low residual stress. Resultantly, the coating has a high interfacial bonding strength of 6.79 MPa due to the difficult crack initiation and propagation as well as the limited strain localization. The coated C/CA shows good ablation resistance with a linear ablation rate of 0.62 μm/s at 1900 °C for 600 s and remarkable thermal insulation with a large temperature drop of 930 °C in 10 mm thickness. The strategy of a combination of dense CVD and gradient ceramization layers can be extended to other components with excellent high temperature properties such as ZrC, HfC, which will facilitate the improvement of the ablation performance of C/CA in ultra-high temperatures. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) and calcium (Ca) are two essential macronutrients in plants; however, the characteristics of Mg and Ca concentrations in organ, subcellular and chemical forms and their relationships in citrus plants, especially under varying Mg supply, are not well understood. In this study, Citrus sinensis seedlings (cv. Xuegan) were cultivated in conditions of Mg deficiency (0 mmol Mg2+ L−1) and Mg sufficiency (2 mmol Mg2+ L−1) to investigate the responses of Mg and Ca homeostasis in different organs and fractions. Compared with Mg sufficiency, Mg deficiency significantly decreased root and shoot growth, with the shoot biomass reduction of branch organs was greater than that of parent organs. In addition to increasing the Ca concentration in the parent stem and lateral root organs, Mg deficiency significantly decreased the concentrations and accumulations of Mg and Ca in citrus seedlings, further altering their distribution in different organs. More than 50% of Ca and Mg were sequestrated in the cell wall and soluble fractions, respectively, with Mg concentration decreasing by 15.4% in roots and 46.9% in leaves under Mg deficiency, while Ca concentration decreased by 27.6% in roots and increased by 23.6% in parent leaves. Approximately 90% of Mg exists in inorganic, water-soluble, and pectate and protein-bound forms, and nearly 90% of Ca exists in water-soluble, pectate and protein-bound, phosphate and oxalate acid forms. Except for the decreased inorganic Mg in roots and water-soluble Mg and Ca in leaves, Mg deficiency increased the proportions of Mg and Ca in all chemical forms. However, Mg deficiency generally increased the Ca/Mg ratio in various organs, subcellular and chemical forms, with negative relationships between Mg concentration and Ca/Mg ratio, and the variations of Mg and Ca were highly separated between Mg supply and organs. In conclusion, our results provide insights into the effects of Mg supply on Mg and Ca homeostasis in citrus plants. • More than 50% of Ca and Mg were respectively sequestrated in the cell wall and soluble fractions in citrus seedlings. • Mg deficiency decreased Mg and Ca concentrations in the organ, subcellular and chemical forms. • There was a negative relationship between the Mg concentration and Ca/Mg ratio in various organs and fractions. [ABSTRACT FROM AUTHOR]

Microbial arsenic (As) methylation in paddy soil produces mainly dimethylarsenate (DMA), which can cause physiological straighthead disease in rice. The disease is often highly patchy in the field, but the reasons remain unknown. We investigated within-field spatial variations in straighthead disease severity, As species in rice husks and in soil porewater, microbial composition and abundance of arsM gene encoding arsenite S-adenosylmethionine methyltransferase in two paddy fields. The spatial pattern of disease severity matched those of soil redox potential, arsM gene abundance, porewater DMA concentration, and husk DMA concentration in both fields. Structural equation modelling identified soil redox potential as the key factor affecting arsM gene abundance, consequently impacting porewater DMA and husk DMA concentrations. Core amplicon variants that correlated positively with husk DMA concentration belonged mainly to the phyla of Chloroflexi, Bacillota, Acidobacteriota, Actinobacteriota, and Myxococcota. Meta-omics analyses of soil samples from the disease and non-disease patches identified 5129 arsM gene sequences, with 71% being transcribed. The arsM-carrying hosts were diverse and dominated by anaerobic bacteria. Between 96 and 115 arsM sequences were significantly more expressed in the soil samples from the disease than from the non-disease patch, which were distributed across 18 phyla, especially Acidobacteriota, Bacteroidota, Verrucomicrobiota, Chloroflexota, Pseudomonadota, and Actinomycetota. This study demonstrates that even a small variation in soil redox potential within the anoxic range can cause a large variation in the abundance of As-methylating microorganisms, thus resulting in within-field variation in rice straighthead disease. Raising soil redox potential could be an effective way to prevent straighthead disease., (© The Author(s) 2024. Published by Oxford University Press on behalf of the International Society for Microbial Ecology.)

Inorganic and methylated thioarsenates have recently been reported to form in paddy soil pore waters and accumulate in rice grains. Among them, dimethylmonothioarsenate (DMMTA) is particularly relevant because of its high cytotoxicity and potential misidentification as nonregulated dimethylarsenate (DMA). Studying DMMTA uptake and flag leaf, grain, and husk accumulation in rice plants during grain filling, substantial dethiolation to DMA was observed with only 8.0 ± 0.1, 9.1 ± 0.6, and 1.4 ± 0.2% DMMTA remaining, respectively. More surprisingly, similar shares of DMMTA were observed in control experiments with DMA, indicating in planta DMA thiolation. Exposure of different rice seedling varieties to not only DMA but also to arsenite and monomethylarsenate (MMA) revealed in planta thiolation as a common process in rice. Up to 35 ± 7% DMA thiolation was further observed in the shoots and roots of the model plant Arabidopsis thaliana . Parameters determining the ratio and kinetics of thiolation versus dethiolation are unknown, yet, but less DMA thiolation in glutathione-deficient mutants compared to wild-type plants suggested glutathione concentration as one potential parameter. Our results demonstrate that pore water is not the only source for thioarsenates in rice grains and that especially the currently nonregulated DMA needs to be monitored as a potential precursor of DMMTA formation inside rice plants.

Background: Inorganic arsenic (iAs) is a widespread toxic metalloid. It is well-known that iAs metabolism and its toxicity are mediated by polymorphisms in AS3MT and other genes. However, studies during pregnancy are scarce. We aimed to examine the role of genetic polymorphisms in AS3MT, GSTO2, N6AMT1, MTHFR, MTR, FTCD, CBS, and FOLH1 in iAs methylation efficiency during pregnancy., Methods: The study included 541 pregnant participants from the INMA (Environment and Childhood) Spanish cohort. Using high-performance liquid chromatography coupled to inductively coupled plasma-tandem mass, we measured arsenic (iAs and the metabolites monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)) in urine samples collected during the first trimester. iAs methylation efficiency was determined based on relative concentrations of the As metabolites in urine (%MMA, %DMA, and %iAs). Thirty-two single nucleotide polymorphisms (SNPs) in nine genes were determined in maternal DNA; AS3MT haplotypes were inferred. We assessed the association between genotypes/haplotypes and maternal As methylation efficiency using multivariate linear regression models., Results: The median %MMA and %DMA were 5.3 %, and 89 %, respectively. Ancestral alleles of AS3MT SNPs (rs3740393, rs3740390, rs11191453, and rs11191454) were significantly associated with higher %MMA, %iAs, and lower %DMA. Pregnant participants with zero copies of the GGCTTCAC AS3MT haplotype presented a higher %MMA. Statistically significant associations were also found for the FOLH1 SNP rs202676 (β 0.89 95%CI: 0.24, 1.55 for carriers of the G allele vs. the A allele)., Conclusions: Our study shows that ancestral alleles in AS3MT polymorphisms were associated with lower As methylation efficiency in early pregnancy and suggests that FOLH1 also plays a role in As methylation efficiency. These results support the hypothesis that As metabolism is multigenic, being a key element for identifying susceptible populations., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Microorganisms play a key role in arsenic (As) biogeochemistry, transforming As species between inorganic and organic forms and different oxidation states. Microbial As methylation is enhanced in anoxic paddy soil, producing primarily dimethylarsenic (DMAs), which can cause rice straighthead disease and large yield losses. DMAs can also be demethylated in paddy soil, but the microorganisms driving this process remain unclear. In this study, we showed that the enrichment culture of methylotrophic methanogens from paddy soil demethylated pentavalent DMAs(V) efficiently. DMAs(V) was reduced to DMAs(III) before demethylation. 16S rRNA gene diversity and metagenomic analysis showed that Methanomassiliicoccus dominated in the enrichment culture, with Methanosarcina and Methanoculleus also being present. We isolated Methanomassiliicoccus luminyensis CZDD1 and Methanosarcina mazei CZ1 from the enrichment culture; the former could partially demethylate trivalent DMAs(III) but not DMAs(V) and the latter could demethylate neither. Addition of strain CZDD1 to the enrichment culture greatly accelerated DMAs(V) demethylation. Demethylation of DMAs(V) in the enrichment culture was suppressed by ampicillin, suggesting the involvement of bacteria. We isolated three anaerobic bacterial strains including Clostridium from the enrichment culture, which could produce hydrogen and reduce DMAs(V) to DMAs(III). Furthermore, augmentation of the Methanomassiliicoccus-Clostridium coculture to a paddy soil decreased DMAs accumulation by rice and alleviated straighthead disease. The results reveal a synergistic relationship whereby anaerobic bacteria reduce DMAs(V) to DMAs(III) for demethylation by Methanomassiliicoccus and also produce hydrogen to promote the growth of Methanomassiliicoccus; enhancing their populations in paddy soil can help alleviate rice straighthead disease., (© 2023. The Author(s).)

To assess the two most toxicologically relevant species of As, namely arsenite (As(III)) and arsenate (As(V)), chromatographic separations often require two separate chromatographic columns to address the co-elution of arsenobetaine (AsB) with As(III). This issue is typically observed using conventional isocratic methods on anion exchange columns, increasing cost and analysis time. Here, we optimize the extraction of inorganic As from a lichen air biomonitor and develop an isocratic method for the chromatographic separation of five common As species on a PRP X-100 anion exchange column, resulting in the complete baseline separation of all species under study. This method was then applied to lichen biomonitors from an urban and rural site to demonstrate its use. In order of abundance, the various arsenic species in lichens from the urban site in South Africa were As(V) > As(III) > AsB > dimethylarsinic acid (DMA) > monomethylarsonic acid (MMA), and As(V) > AsB > As(III) > DMA > MMA for the rural site, where MMA was present in extremely low, non-quantifiable concentrations in lichens from both sites. Total concentrations of As were higher in samples from the urban site (6.43 ± 0.25 μg/g) than in those from the rural site (1.87 ± 0.05 μg/g), with an overall extraction efficiency of 19% and 40%, respectively. The optimized method utilized relatively inexpensive solvents and is therefore low-cost and eco-friendly in comparison with conventional chromatographic techniques. This is the first study which addresses the optimized extraction and characterization of As species in a South African lichen biomonitor of air pollution. [ABSTRACT FROM AUTHOR]

Due to the toxic effect of boron and its compounds on specified concentrations, it is necessary for boron and its compounds to be eliminated from wastewater prior to the discharging into the receiving environment. Today, it is introduced by a numerous of researchers that the removal of boron through the various physicochemical methods is applicable. In this paper, the elimination of boron from industrial wastewater by means of chemical precipitation with Ca(OH)2 as inorganic salt has been studied. Through the tests pH, boron concentration, Ca(OH)2 amount and temperature have been utilized as the parameters of the study. Ultimately, under optimum pH, by increasing the concentration, the temperature and the amount of Ca(OH)2, elimination of boron up to 98% has been achieved. It is considered that some part of the eliminated boron has been chemically precipitated as calcium borate while another part has been eliminated by the precipitation together with the ensued calcium sulphate. [ABSTRACT FROM AUTHOR]

Arsenic species contaminate food and water, with typical dietary intake below 1 μg/kg bw/d. Exposure to arsenic in heavily contaminated drinking water is associated with human diseases, including cardiovascular and respiratory disorders, diabetes, and cancer. Dietary intake assessments show that rice and seafood are the primary contributors to intake of both inorganic arsenic and dimethylarsinic acid (DMAV) and at similar magnitudes. DMAV plays a central role in the toxicology of arsenic because enzymatic methylation of arsenite produces DMAV as the predominant metabolite, which may promote urinary clearance but also generates reactive intermediates, predominantly DMAIII, that bind extensively to cellular thiols. Both inorganic arsenic and DMAV are carcinogenic in chronically exposed rodents. This study measured pentavalent and trivalent arsenic species in blood and tissues after oral and intravenous administration of DMAV (50 μg As/kg bw). DMAV underwent extensive first-pass metabolism in the intestine and liver, exclusively by reduction to DMAIII, which bound extensively to blood and tissues. The results confirm a role for methylation-independent reductive metabolism in producing fluxes of DMAIII that presumably underlie arsenic toxicity and indicate the need to include all dietary intake of inorganic arsenic and DMAV in risk assessments. • Extensive first-pass metabolism of ingested DMAV occurs in the intestine and liver. • Bound DMAIII was observed in all tissues analyzed, but was lowest in muscle and brain. • Methylation-independent reductive metabolism of DMAV produces reactive trivalent species. • Dietary intake of both inorganic arsenic and DMAV should be included in risk assessments. [ABSTRACT FROM AUTHOR]

Early-life exposure to inorganic arsenic (iAs) may adversely impact health later in life. To date, evidence of iAs adverse effects on children's neurodevelopment comes mainly from populations highly exposed to contaminated water with conflicting results. Little is known about those effects among populations with low iAs exposure from food intake. We investigated the cross-sectional association between exposure to iAs and neurodevelopment scores among children living in Spain whose main route of exposure was diet. Arsenic species concentrations in urine from 400 children was determined, and the sum of urinary iAs, dimethylarsinic acid, and monomethylarsonic acid was used to estimate iAs exposure. The McCarthy Scales of Children's Abilities was used to assess children's neuropsychological development at about 4–5 years of age. The median (interquartile range) of children's sum of urinary iAs, MMA, and DMA was 4.85 (2.74–7.54) μg/L, and in adjusted linear regression analyses the natural logarithm transformed concentrations showed an inverse association with children's motor functions (β, [95% confidence interval]; global scores (−2.29, [-3.95, −0.63])), gross scores (−1.92, [-3.52, −0.31]) and fine scores (−1.54, [-3.06, −0.03]). In stratified analyses by sex, negative associations were observed with the scores in the quantitative index (−2.59, [-5.36, 0.17]) and working memory function (−2.56, [-5.36, 0.24]) only in boys. Our study suggests that relatively low iAs exposure may impair children's neuropsychological development and that sex-related differences may be present in susceptibility to iAs related effects; however, our findings should be interpreted with caution given the possibility of residual confounding. • Relatively low iAs exposure may impair children's neuropsychological development. • Sex-related differences may be present in iAs toxic effect susceptibility. • Early-life iAs exposure from food intake should be minimized. [ABSTRACT FROM AUTHOR]

Almost every organ in the human body can be affected by arsenic (As) exposure associated with various industrial processes, as well as with contaminated food, drinking water and polluted air. Much is known about high exposure to inorganic As but there is little data on the metabolic changes connected to a low exposure e.g. in people living in smelter areas. The objectives of the study were: (1) characterise urinary concentration of total arsenic (AsT) in Polish inhabitants of the vicinity of a copper smelter area, (2) speciation analysis of various forms of arsenic in girls (GL), boys (BL), women (WL) and men (ML) with a slightly elevated AsT concentration and age/sex matched groups with a substantially higher AsT concentration, (GH, BH, WH and MH – respectively), (3) comparison of metabolomics profiles of urine between the age/sex matched people with low and high AsT concentrations. Urine samples were analysed for total arsenic and its chemical forms (AsIII; AsV, methylarsonic acid, dimethylarsinic acid, arsenobetaine) using HPLC-ICP-MS. Untargeted metabolomics analysis of the urine samples was performed using UPLC system connected to Q-TOF-MS equipped with an electrospray source. The XCMS Online program was applied for feature detection, retention time correction, alignment, statistics, annotation and identification. Potentially identified compounds were fragmented and resulting spectra were compared to the spectra in the Human Metabolome Database. Urine concentration of AsT was, as follows: GL 16.40 ± 0.83; GH 115.23 ± 50.52; BL 16.48 ± 0.83; BH 95.00 ± 50.03; WL 16.93 ± 1.21; WH 170.13 ± 96.47; ML 16.91 ± 1.20; MH 151.71 ± 84.31 μg/l and percentage of arsenobetaine in AsT was, as follows: GL 65.5 ± 13.8%, GH 87.2 ± 4.7%, BL 59.8 ± 12.5%, BH 90.5 ± 2.4%, WL 50.8 ± 14.1%, WH 90.4 ± 3.5%, ML 53.3 ± 10.0%, MH 74.6 ± 20.2%. In the people with low and high AsT concentrations there were significant differences in the intensity of signal (is.) from numerous compounds being metabolites of neurotransmitters, nicotine and hormones transformation (serotonin in the girls and women; catecholamines in the girls, boys and women; mineralocorticoids and glucocorticoids in the boys, androgens in the women and men and nicotine in the boys, women and men). These changes might have been associated with higher is. from metabolites of leucine, tryptophan, purine degradation (in the GH, WH), urea cycle (in the WH and MH), glycolysis (in the WH) and with lower is. from metabolites of tricarboxylic acid cycle (in the BH) in comparison with low AsT matched groups. In the MH vs. ML higher is. from metabolite of lipid peroxidation (4-hydroxy-2-nonenal) was observed. Additionally, the presence of significant differences was reported in is. from food components metabolites, which might have modulated the negative effects of As (vitamin C in the girls, boys and men, vitamin B 6 in the girls, boys and women as well as phenolic compounds in the boys and girls). We hypothesize that the observed higher is. from metabolites of sulphate (in MH) and glucoronate degradation (in BH, WH and MH) than in the matched low AsT groups may be related to the impaired glucuronidation and sulfonation and higher is. from catecholamines, nicotine and hormones. Our results indicated that even a low exposure to As is associated with metabolic changes and that urine metabolomics studies could be a good tool to reflect their wide spectrum connected to specific environmental exposure to As, e.g. in smelter areas. [ABSTRACT FROM AUTHOR]

High arsenic (As) concentrations are found in marine clams, usually as less-toxic arsenobetaine (AsB). However, when clams were exposed to elevated As concentrations in the environments, As species distribution within them may be altered. This study aimed to determine As bioaccumulation and biotransformation in marine clams (Asaphis violascens) along As concentration gradients for 10 days. Nine treatments of dissolved As exposure [control, 1, 3 (low), 10, 20 (high) mg/L As(III) and As(V)] were performed. Clams could biotransform low-levels of inorganic As efficiently, while they had lower biotransformation efficiencies when exposed to high As concentrations. AsB decreased with increasing As(III) and As(V) concentrations, while dimethylarsinic acid exhibited as a predominant As species in 3 mg/L exposure treatments. These results suggested that As methylation, synthesis and/or degradation of AsB should be affected by exposure concentrations. Therefore, these toxic As species within clams may cause a potential toxicological hazard to human beings. [ABSTRACT FROM AUTHOR]

The chemical composition of wood depends on many factors, including plant growth conditions. Among the many dangerous elements it was decided in this study to select arsenic in various forms: As(III), As(V) and cacodylic acid (DMAA), as well as various concentrations and mutual combinations. The experiment was conducted on 1-year old elm seedlings planted in pots with an addition of Knop medium and arsenic. Supplementation of the substrate with each arsenic form caused changes in contents of cellulose and lignin as well as extractive substances and those soluble in 1% NaOH. Arsenic also led to changes in the structure of basic wood components. The FTIR analysis showed the greatest changes under the influence of As(V), As(III)/As(V)/DMA. Despite high arsenic concentration in the substrate 1-year old elm seedlings survived the period of the experiment, thus providing valuable results and broadening our knowledge on the response of trees to the environment contaminated with arsenic. [ABSTRACT FROM AUTHOR]

A new simplified method of flame atomic absorption and emission spectrometry (FAAS/FAES) analysis of red beetroot juices on the content of Ca, K, Mg, and Na was proposed and validated. The method included only appropriate dilution of samples with 0.5 mol L−1 HNO 3 prior to spectrometric measurements and was characterized by precision better than 2% and trueness better than 3%. It was used to verify quality of twelve commercially available red beetroot juices. In addition, chemical fractionation of Ca and Mg was undertaken with the aid of tandem solid phase extraction (SPE) with reversed phase and cation exchange sorptive materials. Three operationally defined fractions, including hydrophobic, residual, and cationic species, were distinguished. On the basis of contributions of these fractions it was presumed that Ca and Mg were organically bound to a high degree, i.e. , on average 86% in case of Ca and 75% in case of Mg. • Red beetroot juices in reference to Ca, K, Mg, and Na studied • Simplified FAAS based method of their determination developed • Chemical fractionation of Ca and Mg by tandem SPE carried out • High contributions of organically bound fractions of Ca and Mg revealed [ABSTRACT FROM AUTHOR]

Arsenic intake in the world is linked with drinking water and food; the main sources of inorganic As (i-As) exposure in food are rice and rice-based products. The consumption of rice in Ecuador is 53.2 kg year−1 and it is the most commonly used cereal for the preparation of many popular dishes especially for subjects with celiac disease. Objectives of this research were: (i) to determine the content of i-As in foods widely consumed by Ecuadorians with celiac disease, (ii) to calculate the i-As dietary intake, and (iii) to model and predict the health risks of the population under study as a result of their exposure to i-As from rice-based food. The estimated daily intakes of Ecuadorian children (below 3 years of age) and adults were established at 0.52 and 0.55 μg kg−1 body weight d−1, respectively. These values were above the lower BMDL01 value established for i-As established by the EFSA; consequently, it can be concluded that health risk cannot be excluded for the Ecuadorian population with celiac disease. [ABSTRACT FROM AUTHOR]

Arsenic and antimony are highly toxic to humans, animals, and plants. Incorporation in alunite, jarosite, and beudantite group minerals can immobilize these elements and restrict their bioavailability in acidic, oxidizing environments. This paper reviews research on the magnitude and mechanisms of incorporation of As and Sb in, and release from, alunite, jarosite, and beudantite group minerals in mostly abiotic systems. Arsenate-for-sulfate substitution is observed for all three mineral groups, with the magnitude of incorporation being beudantite (3 -- 8.5 wt% As) > alunite (3.6 wt% As) > natroalunite (2.8 wt%) > jarosite (1.6 wt% As) > natroalunite (1.5 wt% As) > hydroniumalunite (0.034 wt% As). Arsenate substitution is limited by the charge differences between sulfate ( -- 2) and arsenate ( -- 3), deficiencies in B-cations in octahedral sites and for hydroniumalunite, difficulty in substituting protonated H2O-for-OH- groups. Substitution of arsenate causes increases in the c-axis for alunite and natroalunite, and in the c- and a-axes for jarosite. The degree of uptake depends on, but limited by, the AsO4/TO4 ratio. Aerobic and abiotic As release from alunite and natroalunite is limited, especially between pH 5 and 8. Release of As is also very limited in As-bearing jarosite, natrojarosite, and ammoniumjarosite at pH 8 due to the formation of secondary maghemite, goethite, hematite, and Fe arsenates that resorb the liberated As. Abiotic reductive dissolution of As-bearing jarosite at pH 4, 5.5, and 7 is likewise restricted by the formation of secondary green rust sulfate, goethite, and lepidocrocite that take up the As. Similar processes have been observed for the aerobic dissolution of Pb-As-jarosite (beudantite analog), with secondary Fe oxyhydroxides resorbing the released As at pH 8. Higher amounts of As are released, however, during microbial-driven jarosite dissolution. Natural jarosite has been found to contain up to 5.9 wt% Sb5+ substituting for Fe3+ in the B-site of the mineral structure. Sb(V) is not released from jarosite at pH 4 during abiotic reductive dissolution, but at pH 5.5 and 7, up to 75% of the mobilized Sb can be structurally incorporated into secondary green rust sulfate, lepidocrocite, or goethite. Further research is needed on the co-incorporation of As, Sb, and other ions in, and the uptake and release of Sb from, alunite, jarosite, and beudantite group minerals, the influence of microbes on these processes and the long-term (>1 yr) stability of these minerals. [ABSTRACT FROM AUTHOR]