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1
LUNDH, DAN, DENNIS LARSSON, NOOR NAHAR e ABUL MANDAL. "ARSENIC ACCUMULATION IN PLANTS – OUTLINING STRATEGIES FOR DEVELOPING IMPROVED VARIETY OF CROPS FOR AVOIDING ARSENIC TOXICITY IN FOODS". Journal of Biological Systems 18, n. 01 (marzo 2010): 223–41. http://dx.doi.org/10.1142/s0218339010003214.
Testo completoAbstract (sommario):
Contamination of food with arsenics is a potential health risk for both humans and animals in many regions of the world, especially in Asia. Arsenics can be accumulated in humans, animals and plants for a longer period and a long-term exposure of humans to arsenics results in severe damage of kidney, lever, heart etc. and many other vascular diseases. Arsenic contamination in human may also lead to development of cancer. In this paper we report our results on data mining approach (an in silico analysis based on searching of the existing genomic databases) for identification and characterization of genes that might be responsible for uptake, accumulation or metabolism of arsenics. For these in silico analyses we have involved the model plant Arabidopsis thaliana in our investigation. By employing a system biology model (a kinetic model) we have studied the molecular mechanisms of these processes in this plant. This model contains equations for uptake, metabolism and sequestration of different types of arsenic; As(V), As(III), MMAA and DMAA. The model was then implemented in the software XPP. The model was also validated against the data existing in the literatures. Based on the results of these in silico studies we have developed some strategies that can be used for reducing arsenic contents in different parts of the plant. Data mining experiments resulted in identification of two candidate genes (ACR2, arsenate reductase 2 and PCS1, phytochelatin synthase 1) that are involved either in uptake, transport or cellular localization of arsenic in A. thaliana. However, our system biology model revealed that by increasing the level of arsenate reductase together with an increased rate of arsenite sequestration in the vacuoles (by involving an arsenite efflux pump MRP1/2), it is possible to reduce the amount of arsenics in the shoots of A. thaliana to 11–12%.
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Volynkin, Sergey S., Svetlana B. Bortnikova, Nataliya V. Yurkevich, Olga V. Shuvaeva e Sofia P. Kohanova. "Determination of Arsenic Species Distribution in Arsenide Tailings and Leakage Using Geochemical and Geophysical Methods". Applied Sciences 13, n. 2 (12 gennaio 2023): 1067. http://dx.doi.org/10.3390/app13021067.
Testo completoAbstract (sommario):
This study describes the distribution of arsenic mobile species in the tailings of Cu–Co–Ni–arsenide using the sequential extraction and determining the contents of arsenate (AsV) and arsenite (AsIII). The object of this study is the tailings ponds of the Tuvakobalt plant, which contains waste from the hydrometallurgical arsenide ore processing of the Khovu-Aksy deposit (Republic of Tuva, Russia). A procedure of sequential extraction for arsenic was applied, and it includes the extraction of the following forms: water-soluble, potentially water-soluble and exchangeable, easily sorbed on the surface of carbonates, associated with Fe/Mn oxides/hydroxides, associated with easily oxidized minerals, and accounted for by non-oxidized arsenic minerals. This procedure, which takes into account the peculiarities of the physical and chemical composition of the waste, was supplemented by the analytical determination of the arsenite and arsenate content by using the methods of inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with the hydride generation technique (HG-ICP-AES). The content of the most mobile forms of arsenic, which are water-soluble, potentially water-soluble, and exchangeable species, is equal to 56% of the total arsenic content, 23% and 33% of which are arsenite and arsenate, respectively. Unlike arsenic, the mobile forms of metals have been determined in small quantities. The largest proportion of water-soluble and exchangeable forms is formed by Mg, Ca, and Sr at 11, 9.4, and 20%, respectively (residual and redeposited carbonates). The proportion of water-soluble forms of other metals (Cu, Zn, Co, and Ni) is < 1% or 0. The main part of the metals is adsorbed on the surface of Fe and Mn hydroxides, enclosed in easily and hardly oxidized minerals. In addition to geochemical studies, the presence of leaks from the tailing ponds into ground waters was determined by using electrical resistivity tomography. The data obtained indicate a high environmental hazard of tailings and the possibility of water-soluble and highly toxic arsenic compounds entering ground waters and aquifers.
3
Castriota, Felicia, Peter-James H. Zushin, Sylvia S. Sanchez, Rachael V. Phillips, Alan Hubbard, Andreas Stahl, Martyn T. Smith, Jen-Chywan Wang e Michele A. La Merrill. "Chronic arsenic exposure impairs adaptive thermogenesis in male C57BL/6J mice". American Journal of Physiology-Endocrinology and Metabolism 318, n. 5 (1 maggio 2020): E667—E677. http://dx.doi.org/10.1152/ajpendo.00282.2019.
Testo completoAbstract (sommario):
The global prevalence of type 2 diabetes (T2D) has doubled since 1980. Human epidemiological studies support arsenic exposure as a risk factor for T2D, although the precise mechanism is unclear. We hypothesized that chronic arsenic ingestion alters glucose homeostasis by impairing adaptive thermogenesis, i.e., body heat production in cold environments. Arsenic is a pervasive environmental contaminant, with more than 200 million people worldwide currently exposed to arsenic-contaminated drinking water. Male C57BL/6J mice exposed to sodium arsenite in drinking water at 300 μg/L for 9 wk experienced significantly decreased metabolic heat production when acclimated to chronic cold tolerance testing, as evidenced by indirect calorimetry, despite no change in physical activity. Arsenic exposure increased total fat mass and subcutaneous inguinal white adipose tissue (iWAT) mass. RNA sequencing analysis of iWAT indicated that arsenic dysregulated mitochondrial processes, including fatty acid metabolism. Western blotting in WAT confirmed that arsenic significantly decreased TOMM20, a correlate of mitochondrial abundance; PGC1A, a master regulator of mitochondrial biogenesis; and, CPT1B, the rate-limiting step of fatty acid oxidation (FAO). Our findings show that chronic arsenic exposure impacts the mitochondrial proteins of thermogenic tissues involved in energy expenditure and substrate regulation, providing novel mechanistic evidence for arsenic’s role in T2D development.
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Shakya, S., e B. Pradhan. "Characterization of Dietzia natronolimnaea ASO3 Isolated from Arsenic Anriched Water Sources for its Potential to Arsenic Resistance and Removal". Journal of Institute of Medicine Nepal 36, n. 1 (30 aprile 2014): 50–57. http://dx.doi.org/10.59779/jiomnepal.579.
Testo completoAbstract (sommario):
Introduction: Arsenic is a known toxic metalloid ubiquitous in nature and exposure can occur from natural and anthropogenic sources. In organic arsenic both arsenite and arsenate constitute the highest toxicological risk associated with arsenic in drinking water. This study presents the arsenic resistance and removal capacity of a bacterial strain indigenous to arsenic enriched water of Rautahat district, Nepal. Methods: Identification was carried out by phenotypic and 16S rDNA sequence analysis. The optimal growth conditions regarding temperature, hydrogen ion concentration and salinity; growth kinetics in presence and absence of arsenic, determination of maximum arsenic tolerance concentration, sensitivity to antibiotics, plasmid mediated resistance as well as arsenate reduction and arsenite oxidation and finally arsenic removal potential was determined. Results: The bacterium, Dietzia natronolimnaea ASO3 showed relatively high resistance to arsenate upto 37,460 mg/l and arsenite up to 374.6 mg/l. It showed optimal growth at 30°C in pH 8. The bacterium conferred resistance to penicillin and removed 47% of arsenite and 51% of arsenate from the medium amended with 200 mg/l arsenate and 74.92mg/l arsenite respectively. Conclusion: The higher arsenic tolerance to both arsenate and arsenite species with potential for their removal can be explored further for arsenic mitigation and mobilization study.
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Dong, Owen, Michael Powers, Zijuan Liu e Masafumi Yoshinaga. "Arsenic Metabolism, Toxicity and Accumulation in the White Button Mushroom Agaricus bisporus". Toxics 10, n. 10 (22 settembre 2022): 554. http://dx.doi.org/10.3390/toxics10100554.
Testo completoAbstract (sommario):
Mushrooms have unique properties in arsenic metabolism. In many commercial and wild-grown mushrooms, arsenobetaine (AsB), a non-toxic arsenical, was found as the dominant arsenic species. The AsB biosynthesis remains unknown, so we designed experiments to study conditions for AsB formation in the white button mushroom, Agaricus bisporus. The mushrooms were treated with various arsenic species including arsenite (As(III)), arsenate (As(V)), methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAsO), and their accumulation and metabolism were determined using inductively coupled mass spectrometer (ICP-MS) and high-pressure liquid chromatography coupled with ICP-MS (HPLC-ICP-MS), respectively. Our results showed that mycelia have a higher accumulation for inorganic arsenicals while fruiting bodies showed higher accumulation for methylated arsenic species. Two major arsenic metabolites were produced in fruiting bodies: DMAs(V) and AsB. Among tested arsenicals, only MAs(V) was methylated to DMAs(V). Surprisingly, AsB was only detected as the major arsenic product when TMAsO was supplied. Additionally, AsB was only detected in the fruiting body, but not mycelium, suggesting that methylated products were transported to the fruiting body for arsenobetaine formation. Overall, our results support that methylation and AsB formation are two connected pathways where trimethylated arsenic is the optimal precursor for AsB formation.
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Kim, Hyojin, Yangwon Jeon, Woonwoo Lee, Geupil Jang e Youngdae Yoon. "Shifting the Specificity of E. coli Biosensor from Inorganic Arsenic to Phenylarsine Oxide through Genetic Engineering". Sensors 20, n. 11 (30 maggio 2020): 3093. http://dx.doi.org/10.3390/s20113093.
Testo completoAbstract (sommario):
It has recently been discovered that organic and inorganic arsenics could be detrimental to human health. Although organic arsenic is less toxic than inorganic arsenic, it could form inorganic arsenic through chemical and biological processes in environmental systems. In this regard, the availability of tools for detecting organic arsenic species would be beneficial. Because As-sensing biosensors employing arsenic responsive genetic systems are regulated by ArsR which detects arsenics, the target selectivity of biosensors could be obtained by modulating the selectivity of ArsR. In this study, we demonstrated a shift in the specificity of E. coli cell-based biosensors from the detection of inorganic arsenic to that of organic arsenic, specifically phenylarsine oxide (PAO), through the genetic engineering of ArsR. By modulating the number and location of cysteines forming coordinate covalent bonds with arsenic species, an E. coli cell-based biosensor that was specific to PAO was obtained. Despite its restriction to PAO at the moment, it offers invaluable evidence of the potential to generate new biosensors for sensing organic arsenic species through the genetic engineering of ArsR.
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Percy, Andrew J., e Jürgen Gailer. "Methylated Trivalent Arsenic-Glutathione Complexes are More Stable than their Arsenite Analog". Bioinorganic Chemistry and Applications 2008 (2008): 1–8. http://dx.doi.org/10.1155/2008/539082.
Testo completoAbstract (sommario):
The trivalent arsenic glutathione complexes arsenic triglutathione, methylarsonous diglutathione, and dimethylarsinous glutathione are key intermediates in the mammalian metabolism of arsenite and possibly represent the arsenic species that are transported from the liver to the kidney for urinary excretion. Despite this, the comparative stability of the arsenic-sulfur bonds in these complexes has not been investigated under physiological conditions resembling hepatocyte cytosol. Using size-exclusion chromatography and a glutathione-containing phosphate buffered saline mobile phase (5 or 10 mM glutathione, pH 7.4) in conjunction with an arsenic-specific detector, we chromatographed arsenite, monomethylarsonous acid, and dimethylarsinous acid. The on-column formation of the corresponding arsenic-glutathione complexes between 4 and37°C revealed that methylated arsenic-glutathione complexes are more stable than arsenic triglutathione. The relevance of these results with regard to the metabolic fate of arsenite in mammals is discussed.
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Hoque, M. M., S. Rahman, M. E. Hoque, M. J. Ara e M. R. Jamal. "Arsenic pollution and its impact on agricultural production, including the ecosystem services delivered by biodiversity". Journal of Science Technology and Environment Informatics 13, n. 01 (15 febbraio 2024): 827–39. http://dx.doi.org/10.18801/jstei.130124.83.
Testo completoAbstract (sommario):
Arsenic (As), a noxious metal(loid) widely available in the biosphere, originates mainly from geogenic and anthropogenic origin. Massive global development and industrialization, using pesticides carrying arsenic, arsenical animal feeds, medicine, mining, aquifer sediments, coal burning, and microbial and natural processes continuously release this obnoxious bane to the natural environment and pollute soil and water. Inorganic (iAs) species, mainly arsenate and arsenite, are comparatively more lethal than methylated species. However, pentavalent [As (V)] organic species are nearly non-toxic. An elevated level of arsenic has been found in various crops and feeds consumed by humans and animals. This notable carcinogen threatens human health by drinking arsenic-polluted freshwater and/or ingesting arsenic-adulterated food like cereals, fruits and vegetables grown in arsenic-polluted soil or grown using arsenic-rich irrigation water. Arsenic pollution exerts an irreversible harmful effect on the aquatic and terrestrial ecosystem as well. Much research has been carried out in the last couple of centuries on arsenic pollution and reported its ability to influence the agro-ecosystem to a great extent, including plant accumulation, phytotoxicity, and land degradation. However, underground water is considered the principal source of arsenic pollution, Iron plaque, sulphur oxides, organic matter, microbiome activities and many other factors responsible for speciation, bioavailability and toxicity of As to the environment. This review attempts to comprehend the global arsenic pollution occurrence, its forms, bioavailability and toxicity to humans and microbiota, translocation and accumulation in plants and impact on crop yield. Besides providing the insights, the ultimate targets of this desktop study are to ascertain probable knowledge gaps linked to crop productivity and ecosystem benefit losses that need further investigation.
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Chang, Jin-Soo, Hyun-Jung Kim, Won-Seok Kim e Seyong Lee. "Ars Genotype of Arsenic Oxidizing Bacteria and Detoxification". Journal of Korean Society of Environmental Engineers 46, n. 5 (31 maggio 2024): 185–94. http://dx.doi.org/10.4491/ksee.2024.46.5.185.
Testo completoAbstract (sommario):
Objectives:The objectives of this study is bioremediation and detoxification of arsenite using arsenic resistance system (ars) genotypes of Arsenic Oxidizing Bacteria (AOB) isolated from highly As-contaminated mine.Methods:Bacterial strains that are resistant to arsenic were isolated from the Samkwang mine. The identification of AOB was conducted by analyzing the 16S rRNA gene using universal primers. To determine the genotypes of the arsenic resistance system (ars), specific primers were used for each gene. The extent of arsenic resistance was measured, and the efficiency of arsenite oxidation was assessed through a batch test. Arsenic concentration was measured using ICP-MS.Results and Discussion:The arsenic concentrations at site 1 of the Samkwang mine were found to be 1,322 mg/kg. This concentration is 26.4 times higher than the standard for soil pollution concerns (50 mg/kg) and 8.8 times higher than the standard for soil pollution measures (150 mg/kg). The appropriate remediation is studied such as bacterial remediation. The three efficient AOBs were identified as Agrobacterium tumefaciens EBC-SK1 (MF928870), Ochrobactrum anthrophi EBC-SK4 (MF928873), Ochrobactrum anthrophi EBC-SK12 (MF928881), respectively. The arsenic resistance system (ars) genotype were detected, which is the leader genes of the arsenic oxidation system (arsR and arsD), and the membrane gene (arsB). The arsB is involved in the encoding of the efflux/influx pumping system and moves arsenite into the bacterial cells. Arsenite-oxidizing (aox) genes are activated to oxidize arsenite into arsenate. The AOBs biotransform arsenite to arsenate with the regulation of ars genes, which detoxify highly As-contaminated mine.Conclusion:The AOBs from Samkwang mine are known for their resistance to highly toxic arsenic environments. They play a crucial role in the bioremediation of abandoned mines by transforming As(III) into As(V) through biotransformation.
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Isokpehi, Raphael D., Udensi K. Udensi, Shaneka S. Simmons, Antoinesha L. Hollman, Antia E. Cain, Samson A. Olofinsae, Oluwabukola A. Hassan et al. "Evaluative Profiling of Arsenic Sensing and Regulatory Systems in the Human Microbiome Project Genomes". Microbiology Insights 7 (gennaio 2014): MBI.S18076. http://dx.doi.org/10.4137/mbi.s18076.
Testo completoAbstract (sommario):
The influence of environmental chemicals including arsenic, a type 1 carcinogen, on the composition and function of the human-associated microbiota is of significance in human health and disease. We have developed a suite of bioinformatics and visual analytics methods to evaluate the availability (presence or absence) and abundance of functional annotations in a microbial genome for seven Pfam protein families: As(III)-responsive transcriptional repressor (ArsR), anion-transporting ATPase (ArsA), arsenical pump membrane protein (ArsB), arsenate reductase (ArsC), arsenical resistance operon transacting repressor (ArsD), water/glycerol transport protein (aquaporins), and universal stress protein (USP). These genes encode function for sensing and/or regulating arsenic content in the bacterial cell. The evaluative profiling strategy was applied to 3,274 genomes from which 62 genomes from 18 genera were identified to contain genes for the seven protein families. Our list included 12 genomes in the Human Microbiome Project (HMP) from the following genera: Citrobacter, Escherichia, Lactobacillus, Providencia, Rhodococcus, and Staphylococcus. Gene neighborhood analysis of the arsenic resistance operon in the genome of Bacteroides thetaiotaomicron VPI-5482, a human gut symbiont, revealed the adjacent arrangement of genes for arsenite binding/transfer (ArsD) and cytochrome c biosynthesis (DsbD_2). Visual analytics facilitated evaluation of protein annotations in 367 genomes in the phylum Bacteroidetes identified multiple genomes in which genes for ArsD and DsbD_2 were adjacently arranged. Cytochrome c, produced by a posttranslational process, consists of heme-containing proteins important for cellular energy production and signaling. Further research is desired to elucidate arsenic resistance and arsenic-mediated cellular energy production in the Bacteroidetes.
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Miyashita, Shin-ichi, Chisato Murota, Keisuke Kondo, Shoko Fujiwara e Mikio Tsuzuki. "Arsenic metabolism in cyanobacteria". Environmental Chemistry 13, n. 4 (2016): 577. http://dx.doi.org/10.1071/en15071.
Testo completoAbstract (sommario):
Environmental context Cyanobacteria are ecologically important, photosynthetic organisms that are widely distributed throughout the environment. They play a central role in arsenic transformations in terms of both mineralisation and formation of organoarsenic species as the primary producers in aquatic ecosystems. In this review, arsenic resistance, transport and biotransformation in cyanobacteria are reviewed and compared with those in other organisms. Abstract Arsenic is a toxic element that is widely distributed in the lithosphere, hydrosphere and biosphere. Some species of cyanobacteria can grow in high concentrations of arsenate (pentavalent inorganic arsenic compound) (100mM) and in low-millimolar concentrations of arsenite (trivalent inorganic arsenic compound). Arsenate, which is a molecular analogue of phosphate, is taken up by cells through phosphate transporters, and inhibits oxidative phosphorylation and photophosphorylation. Arsenite, which enters the cell through a concentration gradient, shows higher toxicity than arsenate by binding to sulfhydryl groups and impairing the functions of many proteins. Detoxification mechanisms for arsenic in cyanobacterial cells include efflux of intracellular inorganic arsenic compounds, and biosynthesis of methylarsonic acid and dimethylarsinic acid through methylation of intracellular inorganic arsenic compounds. In some cyanobacteria, ars genes coding for an arsenate reductase (arsC), a membrane-bound protein involved in arsenic efflux (arsB) and an arsenite S-adenosylmethionine methyltransferase (arsM) have been found. Furthermore, cyanobacteria can produce more complex arsenic species such as arsenosugars. In this review, arsenic metabolism in cyanobacteria is reviewed, compared with that in other organisms. Knowledge gaps remain regarding both arsenic transport (e.g. uptake of methylated arsenicals and excretion of arsenate) and biotransformation (especially production of lipid-soluble arsenicals). Further studies in these areas are required, not only for a better understanding of the role of cyanobacteria in the circulation of arsenic in aquatic environments, but also for their application to arsenic bioremediation.
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Boujedaini, Naoual, Laurence Terzan e Anisur Rahman Khuda-Bukhsh. "Summary of four scientific studies on Arsenicum album high dilution effect against Arsenic intoxication in mice". International Journal of High Dilution Research - ISSN 1982-6206 11, n. 40 (21 dicembre 2021): 150–51. http://dx.doi.org/10.51910/ijhdr.v11i40.606.
Testo completoAbstract (sommario):
Background: Groundwater arsenic affects millions of people in about 20 countries. In West Bengal (India) and Bangladesh alone over 100 million people are exposed. The arsenic concentration in contaminated groundwater in Bangladesh was above the maximum permissible level of 0.05 mg/l as recommended by WHO for developing countries [1]. Drinking water is not the only source of poisoning. In arsenic contaminated areas, crops, vegetables, cereals, poultry, cattle, etc, also contain traces of arsenic. Chronic arsenic intoxication has been associated with several diseases such as melanosis, leuco-melanosis, hyperkeratosis, oedema, skin cancer…
Cazin et al [2], have demonstrated the effect of high dilutions of arsenic compounds. They noted increased arsenic elimination from blood through urine and faeces in intoxicated rats. According to these research, the aim of Khuda Buksh studies [3-4-5] was to investigate whether high dilution Arsenicum album have any effect on arsenic accumulation in different tissues and to understand also how this high dilution could produce a protective effect on all the different organs.
Methodology: Firstly, the effect of Arsenicum album 30 cH on the amount of arsenic accumulation was determined by spectrophotometric analysis in four tissues namely liver, kidney and testis in mice intoxicated by arsenic. The protective effect in chronic and acute arsenic intoxicated mice of Arsenicum Album 6cH, 30cH and 200cH has been evaluated using not only the activities of enzymatic and biomarker toxicity (aspartate amino transferase (AST), alanine amino transferase (ALT), acid phosphatase (AcP), alkaline phosphatase (AlkP), lipid peroxidation (LPO) and reduced glutathione (GSH)) but also the cytogenetical parameters (chromosome aberrations (CA), mitotic index (MI), sperm head anomaly (SHA) etc., ). Because, it is well demonstrated that these enzymes biomarkers reflect the degree of hepatotoxicity and oxidative stress caused by arsenic intoxication.
Results: Compared to controls, Arsenicum album 30cH induced a significant decrease in accumulation of arsenic in 4 tissues namely liver, spleen, kidney and testis in intoxicated mice. In addition, both Arsenicum album 6cH, 30cH and 200cH reduced chromosome aberrations, sperm head abnormality frequencies and activities of acid and alkaline phosphatases, aspartate and alanine aminotransferases and lipid peroxidation, while mitotic index and activities of glutathione, catalase and succinate dehydrogenase were increased compared to controls.
Conclusion: Altogether, theses results provide evidence of protective potentials of the Arsenicum album dilution against acute and chronic arsenic intoxication in mice. They also offer a new hypothesis that the mechanism of the homeopathic dilution could act through regulation of expression of certain genes. This explanation seems to be plausible because all biomarker tests are regulated by specific genetic regulatory mechanisms [6].
keywords: Arsenicum album, arsenic intoxication, enzymatic and biomarker toxicity.
References:
[1] WHO. WHO Guidelines for Drinking Water Quality, Vol. 2, 2nd edition. Geneva: WHO, 1996, 940–9.
[2] Cazin JC, Cazin M, Gaborit JL, Chaoui A, Boiron J, Belon P, et al. A study of the effect of decimal and centesimal dilutions of arsenic on the retention and mobilization of arsenic in the rat. Hum Toxicol 1987;6:315–20.
[3] Mitra K, Kundu SN, Khuda-Bukhsh AR. Efficacy of a potentized homoeopathic drug (Arsenicum Album-30) in reducing toxic effects produced by of arsenic trioxide in mice. I. On rate accumulation of arsenic in certain vital organs. Comp Ther Med 1998;6:178–84.
[4] Pathikrit Banerjee. Evidences of Protective Potentials of Microdoses of Ultra-high Diluted Arsenic Trioxide in Mice Receiving Repeated Injections of Arsenic Trioxide. eCAM 2009; 1-10.
[5] Pathikrit Banerjee, Comparative Efficacy of Two Microdoses of a Potentized Homeopathic Drug, Arsenicum Album, to Ameliorate Toxicity Induced by Repeated Sublethal Injections of Arsenic Trioxide in Mice. Pathobiology 2008;75:156–170.
[6]/ Khuda-Bukhsh AR. Potentized homeopathic drugs act through regulation of gene expression: a hypothesis to explain their mechanism and pathways of action in vivo. Comp Ther Med 1997;5:43–6
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Jankong, Patcharin, Cherif Chalhoub, Norbert Kienzl, Walter Goessler, Kevin A. Francesconi e Pornsawan Visoottiviseth. "Arsenic accumulation and speciation in freshwater fish living in arsenic-contaminated waters". Environmental Chemistry 4, n. 1 (2007): 11. http://dx.doi.org/10.1071/en06084.
Testo completoAbstract (sommario):
Environmental context. Inorganic arsenic, a well-known human carcinogen, represents a major worldwide environmental problem because contaminated water supplies have lead to widespread human exposure. This study investigates the arsenic content of freshwater fish from arsenic-contaminated and non-contaminated sites in Thailand, and reports high arsenic concentrations and significant amounts of inorganic arsenic in the edible muscle tissue. The data suggest that freshwater fish may represent a significant source of inorganic arsenic to some human populations. Abstract. Striped snakehead (Channa striata), carnivorous freshwater fish that serve as popular food in Thailand, were collected from a reference site (1.4 µg As L–1) and from two arsenic-contaminated ponds (Pond A, 550 µg As L–1; Pond B, 990 µg As L–1) in southern Thailand and analysed for arsenic by inductively coupled plasma mass spectrometry (ICPMS) and for arsenic species by HPLC-ICPMS performed on aqueous methanol extracts of muscle, liver and gill (n = 3 fish from each site). Mean total arsenic concentration in muscle tissue of C. striata collected from the reference site was 1.9 µg As g–1 (dry mass) while fish from the contaminated sites contained 13.1 µg As g–1 (Pond A) and 22.2 µg As g–1 (Pond B). Liver and gill tissues showed similar increasing arsenic concentrations on going from the reference site to Ponds A and B, with Pond B showing the highest levels. Speciation analysis on the three tissues showed that, although arsenate was the major extractable arsenical in reference fish (e.g. 0.73 µg As g–1 in muscle tissue), dimethylarsinate was by far the dominant arsenic species in fish from the two contaminated sites. Three non-carnivorous fish species (Danio regina, Rasbora heteromorpha and Puntius orphoides), collected from Pond B only, had lower arsenic concentrations (7.9–11.3 µg As g–1 in muscle tissue) than did C. striata, and contained appreciable amounts of trimethylarsine oxide together with two other major arsenicals, arsenate and dimethylarsinate, and smaller quantities of arsenite and methylarsonate. The study shows for the first time a clear effect of water arsenic concentrations on natural fish tissue arsenic concentrations, and is the first report of a freshwater fish species attaining arsenic concentrations comparable with those found in marine fish species. Furthermore, the high concentrations of toxic inorganic arsenic (predominantly arsenate) in the muscle tissue of the edible fish C. striata have human health implications and warrant wider investigations.
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Yean, S., L. Cong, C. T. Yavuz, J. T. Mayo, W. W. Yu, A. T. Kan, V. L. Colvin e M. B. Tomson. "Effect of magnetite particle size on adsorption and desorption of arsenite and arsenate". Journal of Materials Research 20, n. 12 (1 dicembre 2005): 3255–64. http://dx.doi.org/10.1557/jmr.2005.0403.
Testo completoAbstract (sommario):
Numerous studies have examined arsenic adsorption on varying adsorbents including iron oxides, aluminum hydroxides, alumina, and carbon as a means of arsenic removal in drinking water treatments. The objectives of this study were to evaluate the effect of magnetite particle size on the adsorption and desorption behavior of arsenite and arsenate, and to investigate the competitive adsorption between natural organic matter (NOM) and arsenic. Increases in adsorption maximum capacities for arsenite and arsenate were observed with decreasing magnetite particle size. Arsenic desorption is hysteretic, more so with the smaller nanoparticles. Such desorption hysteresis might result from a higher arsenic affinity for magnetite nanoparticles. In the presence of NOM, substantial decrease in arsenic sorption to magnetite nanoparticles was observed. It would be beneficial to thoroughly investigate adsorption and desorption of arsenic on magnetite nanoparticles for further practical purposes.
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He, Dongdong, Yuming Xiong, Li Wang, Wei Sun, Runqing Liu e Tong Yue. "Arsenic (III) Removal from a High-Concentration Arsenic (III) Solution by Forming Ferric Arsenite on Red Mud Surface". Minerals 10, n. 7 (28 giugno 2020): 583. http://dx.doi.org/10.3390/min10070583.
Testo completoAbstract (sommario):
Arsenic (As) is considered one of the most serious inorganic pollutants, and the wastewater produced in some smelters contains a high concentration of arsenic. In this paper, we purified the high-concentration arsenic solution with red mud and Fe3+ synergistically. In this system, arsenite anions reacted with Fe(III) ions to form ferric arsenite, which attached on the surface of red mud particles. The generated red mud/Fe1−x(As)x(OH)3 showed a better sedimentation performance than the pure ferric arsenite, which is beneficial to the separation of arsenic from the solution. The red mud not only served as the carrier, but also as the alkaline agent and adsorbent for arsenic treatment. The effects of red mud dosage, dosing order, pH, and molar ratio of Fe/As on arsenic removal were investigated. The efficiency of arsenic removal increased from a pH of 2 to 6 and reached equilibrium at a pH of 7. At the Fe/As molar ratio of 3, the removal efficiency of arsenic ions with an initial concentration of 500 mg/L reached 98%. In addition, the crystal structure, chemical composition, and morphological properties of red mud and arsenic removal residues (red mud/Fe1−x(As)x(OH)3) were characterized by XRD, XPS, X-ray fluorescence (XRF), SEM-EDS, and Raman spectroscopy to study the mechanism of arsenic removal. The results indicated that most of the arsenic was removed from the solution by forming Fe1−x(As)x(OH)3 precipitates on the red mud surface, while the remaining arsenic was adsorbed by the red mud and ferric hydroxide.
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Zhou, Ting, Jian Mei Zhou, Li Ming Zhou, Wen Li Zhang, Li Juan You, Xin Ming Wang e Jia Yin Cao. "Conversion and Species Distribution Characteristics of Arsenical Chemical Agent in the Soil Contaminated by Chemical Weapons Abandoned by Japan". Advanced Materials Research 955-959 (giugno 2014): 1194–203. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.1194.
Testo completoAbstract (sommario):
In order to phytoremediation the soils contaminated by arsenical chemical weapons abandoned by Japan at some region of Jilin Province and ready for the estimate of the ecological safety, this paper analyzed organic species in soil with GC-MS, disscussed extraction and testing of inorganic arsenic in soil with hydrochloric acid, studied species of arsenic in soil such as available forms, valence state, and combined state, and inferred conversion process of arsenical chemical agent. The results indicate that after simple destroying and long time burial, almost all arsenical chemical agents in soil at this region are converted into inorganic arsenic due to explosion, burning, natural oxidation and microorganism, which primarily exists as As (V). Organic arsenic was only detected at where shells were buried (destroyed), in leaded shells and contaminated soil, with its content 3.65%~32.03%; Organic arsenic content of soil in other part is less than 10%. In contaminated soil of this region, water soluble arsenic and available arsenic extracted from disodium hydrogen phosphate take 0.81~2.58% and 7.49~15.96% of total arsenic respectively. Exchangeable As and binding As (Al-As, Fe-As, reducible As and Ca-As) take 40% of total arsenic, residual As takes 49.38~66.43%. The results may be used as basis for determining remedy methods and assessing ecological safety at this region.
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Drewniak, Lukasz, Renata Matlakowska e Aleksandra Sklodowska. "Microbial Impact on Arsenic Mobilization in Zloty Stok Gold Mine". Advanced Materials Research 71-73 (maggio 2009): 121–24. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.121.
Testo completoAbstract (sommario):
The aim of this review report was to summarize knowledge about arsenic-metabolizing bacteria isolated from Zloty Stok (SW Poland) gold mine and determine their potential role in mobilization of arsenic. Three physiologically different groups of arsenic metabolizing microorganisms (arsenite oxidizers, dissmiliatory arsenate reducers and arsenic resistant microbes) were isolated from the deepest section of Gertruda Adit in Zloty Stok (SW Poland) gold mine. Twenty two strains were isolated from the rock biofilms and seven from arsenic-rich bottom sediments. Analysis of the 16S rRNA gene sequence of isolated bacteria revealed them to be members of the genera: Aeromonas, Arthrobacter, Bacillus, Brevundimonas, Chryseobacterium, Desemzia, Microbacterium, Micrococcus, Paracoccus, Pseudomonas, Rhodococcus, Serratia, Shewanella, Sinorhizobium, Sphingomonas, Stenotrophomonas and Streptomyces. All of the isolated bacteria were resistant to both inorganic arsenic species: arsenate [As(V)] and arsenite [As(III)]. One of the bottom sediments isolates (Sinorhizobium sp. M14) was able to grow on minimal salt medium using arsenite as a source of energy, and was able to release arsenic from arsenopyrite. Two strains (Shewanella sp. O23S and Aeromonas sp. O23A) isolated from bottom sediments were able to grow in the absence of oxygen, by As (V) respiration coupled with lactate oxidation. Based on arsenic metabolic activity of isolated bacteria two different mechanisms of arsenic mobilization from natural minerals (arsenopyrite FeAsS) and secondary ferrous arsenate minerals (scorodite FeAsO4) were proposed.
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Kim, Do Hee, Kyoung Woong Kim e Jaeweon Cho. "Removal and transport mechanisms of arsenics in UF and NF membrane processes". Journal of Water and Health 4, n. 2 (1 giugno 2006): 215–23. http://dx.doi.org/10.2166/wh.2006.0018.
Testo completoAbstract (sommario):
In this study, the removal and transport mechanisms of ionized and non-ionized arsenics through NF and UF membranes were systemically investigated. The charge repulsion between the membrane surface and arsenic ions was an important mechanism for the rejection of ions by a charged membrane. In addition, the effect of J0/k ratio was dependent on the membrane and ion charge, but the cross-flow velocity was not significantly affected. Both diffusion and convection are proved to affect the transport of arsenic ions. The reflection coefficients (σ) of both UF and NF membranes increased with increasing pH; the reflection coefficients of arsenate were higher than those of arsenite under the same operating conditions. The spiral-wound module exhibited slightly higher arsenate removal than the flat-sheet module under the same operating conditions.
19
YAMAZAKI, H., K. ISHII, S. MATSUYAMA, Y. KIKUCHI, Y. TAKAHASHI, A. TERAKAWA, Y. KAWAMURA et al. "PIXE STUDY ON ABSORPTION OF ARSENATE AND ARSENITE BY ARSENIC HYPERACCUMULATING FERN (PTERIS VITTATA)". International Journal of PIXE 18, n. 03n04 (gennaio 2008): 241–52. http://dx.doi.org/10.1142/s0129083508001582.
Testo completoAbstract (sommario):
Pytoremediation using an arsenic hyperaccumulator, Petris vittata L., has generated an increasing interest worldwide due to both environmentally sound and cost effectiveness. However the mechanism of arsenic accumulation by this fern is not clear at this time. This study examined the uptake of arsenate (As(V)) and arsenite (As(III)) by a hydroponic culture of Pteris vittata using both in-air submilli-PIXE for different parts of the fern and in-air micro-PIXE for the tissue cells. These PIXE analysis systems used 3 MeV proton beams from a 4.5-MV single-ended Dynamitron accelerator at Tohoku University, Japan. The fern took up both arsenate and arsenite from hydroponic solutions which were spiked with 50 mg of arsenic per litter. Final amount of arsenic accumulation in the fern is 1,500 mg per kg (wet weight) of the plant biomass in arsenite treatment and 1,100 mg per kg in arsenate treatment. Arsenic accumulation was not observed at the root parts of the ferns. The in-vivo mapping of elements by submilli-PIXE analyses on the fern laminas showed the arsenic accumulation in the edges of a pinna. The micro-PIXE analyses revealed arsenic maps homogeneously distributed in cells of the lamina, stem and rhizome of the fern. These results indicate that arsenic, both arsenate and arsenite in a contaminated medium are translocated quickly from roots to fronds of Pteris vittata, and distributes homogeneously into tissue cells of the fern laminas.
20
Hashem, MA, e K. Toda. "Arsenic leached by step-wise ions addition under aerobic and anaerobic: Speciation by Sequential Hydride Generation Flow Injection Analyzer (SHGFIA)". Bangladesh Journal of Scientific and Industrial Research 49, n. 3 (11 febbraio 2015): 195–98. http://dx.doi.org/10.3329/bjsir.v49i3.22135.
Testo completoAbstract (sommario):
Leaching behavior of arsenic has been investigated by step-wise ions addition of river sediment near arsenic mine; arsenic was contained in sediment 450 mg kg-1. Leachates were characterized by discriminating arsenite and arsenate under both aerobic and anaerobic. Results indicate that arsenite As(III) and arsenate As (V) were leached from the sediments by step-wise ions addition especially phosphate ion enhanced more leaching of arsenic from sediment under anaerobic mostly was As (V). DOI: http://dx.doi.org/10.3329/bjsir.v49i3.22135 Bangladesh J. Sci. Ind. Res. 49(3), 195-198, 2014
21
Fontes, Olney Leite, Fátima Cristiane Lopes Goularte Farhat, Amarilys Toledo Cesar, Marilisa Guimarães Lara, Maria Imaculada Lima Montebelo, Cíntia Maria Bertaglia Luizetto e Marco Vinícius Chaud. "Evaluation of the effect of different concentrations of Arsenicum album 6cH on intoxicated rats". International Journal of High Dilution Research - ISSN 1982-6206 8, n. 28 (28 dicembre 2021): 119–27. http://dx.doi.org/10.51910/ijhdr.v8i28.349.
Testo completoAbstract (sommario):
Aims: Homeopaths diverge on the concept of dose, i.e. the amount of drug that a patient must take to alter his or her state of disease. In order to stimulate reflections on this concept, this study sought to evaluate in vivo the effect of different concentrations of Arsenicum album 6cH prepared according to homeopathic pharmacotechnics. Methods: male Wistar rats were intoxicated with arsenic and then treated with Arsenicum album 6cH and Arsenicum album 6cH diluted at 1%, administered orally. The amount of arsenic retained in the animals’ organism and that eliminated by urine were measured through atomic absorption spectroscopy. Samples of urine were collected before and after intoxication and during treatment. The positive control group (intoxicated animals) and the negative control group (non-intoxicated animals) received only the vehicle used in the preparation of the medicine. Results: Groups treated with Arsenicum album 6cH and Arsenicum album 6cH diluted at 1% eliminated significant amounts of arsenic when compared to the control groups. The group treated with Arsenicum album 6cH eliminated significantly higher amounts of arsenic than the group treated with the diluted medicine at 1%. Conclusion: results suggest that Arsenicum album 6cH should not be diluted as not to compromise its effectiveness in the treatment of rats intoxicated with arsenic.
22
Nawarathne, Madhawa, Ruvini Weerasinghe e Chathuranga Dharmarathne. "Colorimetric and Fluorometric detection of arsenic: arsenate and arsenite". Analytical Methods in Environmental Chemistry Journal 6, n. 01 (28 marzo 2023): 29–57. http://dx.doi.org/10.24200/amecj.v6.i01.224.
Testo completoAbstract (sommario):
Arsenic is a highly toxic metalloid that forms different chemical states in nature, including arsenate and arsenite, as common inorganic forms. Exposure to arsenic may cause adverse effects on human health and the environment. Therefore, the detection of arsenic is critical. Exploring new approaches with low detection ranges and high sensitivity is crucial. This review paper consists of optical methods, including colorimetric and fluorometric methods, which detect arsenite and arsenate. Initially proposed colorimetric approaches such as the Gutzeit and molybdenum blue method can easily to use. However, the production of toxic substances limits their applications. Later, structurally modified molecules, nanoparticle-based assays, and their modifications are used for arsenic detection. Fluorometric methods also have noticeable attention to arsenic detection. Fluorescent approaches reported in this paper are based on semiconductor nanomaterials, other nanomaterials, and their modifications, etc. In addition, arsenate's catalytic and inhibitory activity on enzyme activity can be used to detect arsenic through colorimetric and fluorometric methods. This review highlighted the advantages, disadvantages, comparisons, and uses of colorimetric and fluorometric methods in detecting arsenite and arsenate.
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Chen, Miaomiao, Yi Li, Hong Pan, Jiuwei Teng, Ganesh Bora, Ying Wang e Yi Zhu. "Application of Monoclinic Bismuth Vanadate in Photooxidation of Arsenic-Polluted Water". Transactions of the ASABE 63, n. 6 (2020): 1649–55. http://dx.doi.org/10.13031/trans.13754.
Testo completoAbstract (sommario):
HighlightsPhotooxidation of trivalent arsenic to pentavalent arsenic was catalyzed by s-m BiVO4 under visible light irradiation.The roles of catalyst, light, and oxygen were investigated.The photooxidation mechanism was studied, and a possible reaction route is proposed.Abstract. Oxidation is a necessary step for inorganic arsenic removal. In this study, monoclinic bismuth vanadate (BiVO4) was synthesized to photooxidize trivalent arsenic to pentavalent arsenic in water in the presence of light and oxygen. Light irradiation initiates photooxidation after physical absorption of arsenite on BiVO4. Addition of oxygen slightly improved the photooxidation efficiency. Photooxidation parameters were optimized; 2.6 mM of BiVO4 synthesized at pH 2 was effective to photooxidize 0.1 M of arsenite in alkaline solution, and 99.8% removal of trivalent arsenic was achieved with a photooxidation efficiency of 85.5%. Photooxidation by BiVO4 might be initiated by hydroxyl radicals resulting from irradiation by visible light. Appropriate BiVO4 morphology and alkalinity of the reaction mixture facilitated photooxidation. Keywords: Arsenic, BiVO4, Photooxidation, Speciation.
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Salam, Menaka, Ajit Varma, Divya Chaudhary e Himanshi Aggarwal. "Novel arsenic resistant bacterium Sporosarcina luteola M10 having potential bioremediation properties". Journal of Microbiology & Experimentation 8, n. 6 (22 dicembre 2020): 213–18. http://dx.doi.org/10.15406/jmen.2020.08.00311.
Testo completoAbstract (sommario):
Arsenic (As) is a highly toxic element with great mobility in the environment. If present in high concentrations in soil as well as groundwater, it poses a threat to all living organisms. Although there are many remedial methods which mostly rely on adsorption and filtration, novel technologies using microorganisms are of great attention due to their efficient degradation properties and cost-effectiveness. The present study emphasizes on novel arsenic resistant bacterium which has been isolated from electronic waste contaminated soil samples of Mandoli area in Delhi NCR, India. The isolated bacterium, identified as Sporosarcina luteola through 16S rRNA gene sequencing is tolerant to high levels of arsenic oxyanions. This bacterium designated as Sporosarcina luteola M10 could tolerate arsenate (V) upto 0.2M and arsenite (III) upto 0.01M in minimal medium. The arsenic removal efficiency was 60% of arsenate and 55.5% of arsenite respectively from arsenic amended media at 72 h as detected by atomic absorption spectroscopy. arsC, arsB and aoxB genes encoding arsenate reductase of 280 bp, arsenite transporter of 750 bp and arsenite oxidase of 450 bp respectively were found to be present through PCR amplification of genomic DNA. This is the first report of Sporosarcina luteola extremely resistant to arsenic having potential bioremediation properties.
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Huang, Anhui, Max Teplitski, Bala Rathinasabapathi e Lena Ma. "Characterization of arsenic-resistant bacteria from the rhizosphere of arsenic hyperaccumulatorPteris vittata". Canadian Journal of Microbiology 56, n. 3 (marzo 2010): 236–46. http://dx.doi.org/10.1139/w10-005.
Testo completoAbstract (sommario):
Arsenic hyperaccumulator fern Pteris vittata L. produces large amounts of root exudates that are hypothesized to solubilize arsenic and maintain a unique rhizosphere microbial community. Total heterotrophic counts on rich or defined media supplemented with up to 400 mmol/L of arsenate showed a diverse arsenate-resistant microbial community from the rhizosphere of P. vittata growing in arsenic-contaminated sites. Twelve bacterial isolates tolerating 400 mmol/L of arsenate in liquid culture were identified. Selected bacterial isolates belonging to different genera were tested for their resistance to osmotic and oxidative stresses. Results showed that growth was generally better under osmotic stress generated by arsenic than under that generated by NaCl or PEG 6000, demonstrating that arsenic detoxification metabolism also cross-protected bacterial isolates from arsenic-induced osmotic stress. After 32 h of growth, all arsenate at 1 mmol/L was reduced to arsenite by strains Naxibacter sp. AH4, Mesorhizobium sp. AH5, and Pseudomonas sp. AH21, but arsenite at 1 mmol/L remained unchanged. Sensitivity to hydrogen peroxide was similar to that in broad-host pathogen Salmonella enterica sv. Typhimurium wild type, except strain AH4. The results suggested that these arsenic-resistant bacteria are metabolically adapted to arsenic-induced osmotic or oxidative stresses in addition to the specific bacterial system to exclude cellular arsenic. Both these adaptations contribute to the high arsenic resistance in the bacterial isolates.
26
Miao, Jia-Wei, Shi-Xia Liang, Qin Wu, Jie Liu e An-Sheng Sun. "Toxicology Evaluation of Realgar-Containing Niu-Huang-Jie-Du Pian as Compared to Arsenicals in Cell Cultures and in Mice". ISRN Toxicology 2011 (13 ottobre 2011): 1–6. http://dx.doi.org/10.5402/2011/250387.
Testo completoAbstract (sommario):
Niu-Huang-Jie-Du Pian (NHJD) is a widely used traditional Chinese medicine containing realgar (As4S4). Realgar has been included in many traditional medicines, but is often taken as arsenite for risk assessment. To evaluate true risk of realgar and realgar-containing NHJD, their toxicity was compared with common arsenicals. In cultured cells, the LC50 for NHJD (1200 μM) and realgar (2000 μM) was much higher than arsenite(35 μM), arsenic trioxide (280 μM), and arsenate (400 μM). Acute toxicity in mice showed more severe liver and kidney injury after arsenite or arsenate, but was mild after realgar and NHJD, corresponding to cellular and tissue arsenic accumulation. The expressions of arsenic-sensitive stress gene metallothionein-1 were increased 3–7-folds after arsenite or arsenate, but were unaltered after NHJD and realgar. Thus, realgar and NHJD are much less toxic than arsenite and arsenate. The use of total arsenic to evaluate the safety of realgar and realgar-containing NHJD is inappropriate.
27
Wood, B. Alan, Shinichi Miyashita, Toshikazu Kaise, Andrea Raab, Andrew A. Meharg e Jörg Feldmann. "Arsenic is not stored as arsenite - phytochelatin complexes in the seaweeds Fucus spiralis and Hizikia fusiforme". Environmental Chemistry 8, n. 1 (2011): 30. http://dx.doi.org/10.1071/en10071.
Testo completoAbstract (sommario):
Environmental context Seaweeds hyperaccumulate the toxic metalloid arsenic, but seemingly achieve detoxification by transformation to arsenosugars. The edible seaweed hijiki is a notable exception because it contains high levels of toxic arsenate and arsenite. Terrestrial plants detoxify arsenic by forming arsenite–phytochelatin complexes. The hypothesis that seaweeds also synthesise phytochelatins to bind arsenite as a means of detoxification before arsenosugar synthesis is tested in this investigation. Abstract Phytochelatins (PCs), generic structure [γ-Glu-Cys]n-Gly, are peptides synthesised by terrestrial plants to bind toxic metal(loid)s such as cadmium and arsenic. Seaweeds are arsenic hyperaccumulators, seemingly achieving detoxification via arsenosugar biosynthesis. Whether seaweeds synthesise PCs to aid detoxification during arsenic exposure is unknown. Hizikia fusiforme (hijiki) and Fucus spiralis were used as model seaweeds: the former is known for its large inorganic arsenic concentration, whereas the latter contains mainly arsenosugars. F. spiralis was exposed to 0, 1 and 10 mg L–1 arsenate solutions for 24 h, whereas hijiki was analysed fresh. All samples contained AsIII, glutathione and reduced PC2, identified using HPLC-ICP-MS/ES-MS. Although hijiki contained no AsIII–PC complexes, arsenate exposed F. spiralis generated traces of numerous arsenic compounds that might be AsIII–GS or AsIII–PC2 complexes. AsIII–PC complexes seem not to be a principal storage form for long-term arsenic storage within seaweeds. However, 40 times higher glutathione concentrations were found in hijiki than F. spiralis, which may explain how hijiki deals with its high inorganic arsenic burden.
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Chowdhury, Uttam K. "Groundwater arsenic contamination status and its impact on humans’ health in Bangladesh". Academic Research Journal of Nature and Public Health 1, n. 1 (2022): 1–12. http://dx.doi.org/10.55124/arjn.v1i1.159.
Testo completoAbstract (sommario):
From our preliminary survey (1995 to 2000), 33,092 hand tube wells water samples, collected from all 64 districts and found arsenic in 60 districts above WHO recommended value in drinking water (10 µg/L) and in 50 districts above maximum permissible limit, 50 µg/L. In these 50 districts the actual arsenic status is, 37% contains arsenic less than 10 µg/L, 63% and 42% contain arsenic above 10 µg/L and 50 µg/L, respectively. Total population of these 50 districts is about 104.9 million. This does not mean all populations in the 50 districts are drinking arsenic contaminated water or suffering, but undoubtedly, they are at risk. From our study, it appears that groundwater of Hill Tract and Table Land are almost free from arsenic contamination but that of Flood Plain and Deltaic areas are highly arsenic contaminated. During our preliminary survey, people suffering from arsenical dermal lesions have been identified in 31 out of 33 districts where we had made a preliminary dermatological investigation with medical team. From a random of 18,840 examination people in arsenic affected villages where people were drinking arsenic contaminated groundwater during last 6 years. We had registered 3,427 adults (both females and males) and 298 children (both girls and boys), having arsenical dermal lesions, such as: melanosis, leucomelanosis, keratosis, hyperkeratosis, dorsal, non-petting oedema, gangrene, cancer, etc. If children are included, then 19.77% (n=3,725) have arsenical dermal lesions and for separately adults and children these are 24.52% and 6.13%, respectively.
29
Abbas, Haider, Muhammad Nadeem, Sumbal Tariq, Tahzeeb Zohra, Imran Ahmad, Tayyaba Munawar, Ashraf Hussain e Sidra Ahmad. "Synergistic Effect of Polypyrrole-Polyaniline Conducting Polymer Nanocomposite and Fe3O4 Nanoparticles for Arsenite (III) Adsorption from wastewater". Asian Journal of Applied Chemistry Research 14, n. 3 (6 novembre 2023): 58–67. http://dx.doi.org/10.9734/ajacr/2023/v14i3271.
Testo completoAbstract (sommario):
For treatment of arsenic contaminated water, adsorption of arsenic and it’s reduction are there important processes. Conducting polymer efficiently show the efficient absorption but in use of it there is agglomeration of particles which make its usage difficult. To reduce this problem magnetic property material are used. In this polypyrrole and polyaniline conducting polymers were used. By oxidative polymerization of Polypyrrole and aniline in presence of Fe3O4 by utilizing FeCl3 nanocomposite was manufactured. In this magnetite prevented the agglomeration of particles of polymers and also helped in separation of nanocomposite from solution. Characterization was done by FTIR, SEM and XRD. This nanocomposite removal 88% arsenide (III) from aqueous solution at adsorbent concentration 0.01g and pH=1. Colorimetric method was used which developed complex with arsenite (III) and showed the removal of arsenite (III) from aqueous solution by complex. Separation of nanocomposite became easy due to magnetic properties of magnetite. This could be isolate from aqueous solution by using of strong magnet. This nanocomposite is the promising composite for removal of arsenite (III) from aqueous solution.
30
Carmean, Christopher M., Mizuho Mimoto, Michael Landeche, Daniel Ruiz, Bijoy Chellan, Lidan Zhao, Margaret C. Schulz, Alexandra M. Dumitrescu e Robert M. Sargis. "Dietary Selenium Deficiency Partially Mimics the Metabolic Effects of Arsenic". Nutrients 13, n. 8 (23 agosto 2021): 2894. http://dx.doi.org/10.3390/nu13082894.
Testo completoAbstract (sommario):
Chronic arsenic exposure via drinking water is associated with diabetes in human pop-ulations throughout the world. Arsenic is believed to exert its diabetogenic effects via multiple mechanisms, including alterations to insulin secretion and insulin sensitivity. In the past, acute arsenicosis has been thought to be partially treatable with selenium supplementation, though a potential interaction between selenium and arsenic had not been evaluated under longer-term exposure models. The purpose of the present study was to explore whether selenium status may augment arsenic’s effects during chronic arsenic exposure. To test this possibility, mice were exposed to arsenic in their drinking water and provided ad libitum access to either a diet replete with selenium (Control) or deficient in selenium (SelD). Arsenic significantly improved glucose tolerance and decreased insulin secretion and β-cell function in vivo. Dietary selenium deficiency resulted in similar effects on glucose tolerance and insulin secretion, with significant interactions between arsenic and dietary conditions in select insulin-related parameters. The findings of this study highlight the complexity of arsenic’s metabolic effects and suggest that selenium deficiency may interact with arsenic exposure on β-cell-related physiological parameters.
31
Parada, Humberto, Tianying Wu, Rebecca C. Fry, Laura Farnan, Gary J. Smith, James L. Mohler e Jeannette T. Bensen. "Understanding the Relationship between Environmental Arsenic and Prostate Cancer Aggressiveness among African-American and European-American Men in North Carolina". International Journal of Environmental Research and Public Health 17, n. 22 (12 novembre 2020): 8364. http://dx.doi.org/10.3390/ijerph17228364.
Testo completoAbstract (sommario):
High-level exposure to arsenic, a known carcinogen and endocrine disruptor, is associated with prostate cancer (PCa) mortality. Whether low-level exposure is associated with PCa aggressiveness remains unknown. We examined the association between urinary arsenic and PCa aggressiveness among men in North Carolina. This cross-sectional study included 463 African-American and 491 European-American men with newly diagnosed, histologically confirmed prostate adenocarcinoma. PCa aggressiveness was defined as low aggressive (Gleason score < 7, stage = cT1–cT2, and PSA < 10 ng/mL) versus intermediate/high aggressive (all other cases). Total arsenic and arsenical species (inorganic arsenic (iAsIII + iAsV), arsenobetaine, monomethyl arsenic, and dimethyl arsenic)) and specific gravity were measured in spot urine samples obtained an average of 23.7 weeks after diagnosis. Multivariable logistic regression was used to estimate the covariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for PCa aggressiveness in association with arsenic tertiles/quantiles overall and by race. The highest (vs. lowest) tertile of total arsenic was associated with PCa aggressiveness ORs of 1.77 (95% CI = 1.05–2.98) among European-American men, and 0.94 (95% CI = 0.57–1.56) among African-American men (PInteraction = 0.04). In contrast, total arsenic and arsenical species were not associated with PCa aggressiveness in unstratified models. Low-level arsenic exposure may be associated with PCa aggressiveness among European-Americans, but not among African-Americans.
32
Kato, Tatsuya, Yohei Kawasaki, Masakazu Kadokura, Kohei Suzuki, Yasuhiro Tawara, Yoshiyuki Ohara e Chiharu Tokoro. "Application of GETFLOWS Coupled with Chemical Reactions to Arsenic Removal through Ferrihydrite Coprecipitation in an Artificial Wetland of a Japanese Closed Mine". Minerals 10, n. 5 (23 maggio 2020): 475. http://dx.doi.org/10.3390/min10050475.
Testo completoAbstract (sommario):
Passive systems that utilize a natural power such as a pond, plant, or microorganisms, is expected to be a cost-effective method for acid mine drainage (AMD) treatment. The Ningyo-toge mine, a non-operational uranium mine located in Okayama Prefecture, Japan, generates AMD containing arsenic and iron. To quantitatively study arsenic and iron ion removal in an artificial wetland and pond, chemical reactions were modeled and incorporated into the GETFLOWS (general-purpose terrestrial fluid-flow simulator) software. The chemical reaction models consisted of arsenite and ferrous oxidation equations and arsenic adsorption on ferrihydrite. The X-ray diffraction analysis of sediment samples showed ferrihydrite patterns. These results were consistent with the model for arsenite/ferrous oxidation and arsenic adsorption on ferrihydrite. Geofluid simulation was conducted to simulate mass transfer with the utilized topographic model, inlet flow rate, precipitation, and evaporation. The measured arsenic and iron ions concentrations in solution samples from the wetland and pond, fitted well with the model. This indicated that the main removal mechanism was the oxidation of arsenite/ferrous ions and that arsenic was removed by adsorption rather than dilution.
33
Fouad, Amr A., Waleed H. Albuali, Abdulruhman S. Al-Mulhim e Iyad Jresat. "Protective effect of telmisartan treatment against arsenic-induced testicular toxicity in rats". Zeitschrift für Naturforschung C 70, n. 7-8 (1 luglio 2015): 175–81. http://dx.doi.org/10.1515/znc-2015-5031.
Testo completoAbstract (sommario):
Abstract Oxidative/nitrosative stress, inflammation, and apoptosis play a crucial role in the pathogenesis of arsenic-induced testicular injury. Telmisartan, the angiotensin II-receptor antagonist, possesses antioxidant and anti-inflammatory activities. The protective effect of telmisartan against arsenic-induced testicular damage was investigated in rats. Testicular damage was induced by sodium arsenite (10 mg kg–1/day, p.o., for 2 consecutive days). Telmisartan (10 mg kg–1/day, i.p.) was given for 3 consecutive days, starting 1 day before sodium arsenite administration. Telmisartan significantly attenuated the arsenic-induced decrease in the levels of serum testosterone and testicular reduced glutathione, and significantly decreased the elevation of the levels of testicular malondialdehyde, nitric oxide, and arsenic levels, as well as myeloperoxidase activity resulting from sodium arsenite administration. Histopathological and immunohistochemical examination revealed that telmisartan markedly attenuated testicular tissue changes, and decreased the arsenic-induced expression of vascular endothelial growth factor, inducible nitric oxide synthase, tumor necrosis factor-α, cyclooxygenase-2, nuclear factor-κB, and caspase-3. Telmisartan, via its antioxidant and/or anti-inflammatory effects, may represent a potential candidate to protect against the deleterious effects of arsenic on testicular tissue.
34
Rawlings, A., e S. Seghosime. "Treatment of arsenic contaminated groundwater using Arachis hypogaea". Nigerian Journal of Technology 41, n. 4 (2 novembre 2022): 662–69. http://dx.doi.org/10.4314/njt.v41i4.4.
Testo completoAbstract (sommario):
Arsenic has a detrimental effect on both the environment and humans. In many parts of the world, arsenic has been detected in drinking water sources above acceptable levels. Considering the fact that millions of people are at high risk of arsenic poisoning via water intake, arsenic remediation from drinking water has become a global issue of serious concern. Chemical coagulants are already being used for treatment but their enormous cost, human and environmental issues associated with their use have led to searching for alternatives like natural coagulants (plant-based). In this study, laboratory scale studies using jar test experiments were performed on synthetic arsenite contaminated groundwater to analyse the efficiency of Arachis hypogaea (groundnut seed) on the treatment of arsenic contaminated water. Experiments were carried out using synthetic arsenite contaminated borehole water with pH kept constant at 7.30. Results indicated that groundnut seed extract was able to significantly reduced arsenite in water either as primary coagulant or as coagulant aid (using alum as primary coagulant). As primary coagulant, above 90% arsenite reduction was achieved and as a coagulant aid about 99.97% arsenite reduction was achieved. The pH of the treated water was within neutral (basic) due to the buffering capacity of the seed extract. Therefore, results from this study revealed that groundnut seed has potential for use as primary coagulant or as coagulant aid (with alum as primary coagulant) for the treatment of arsenic contaminated groundwater.
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Rathinasabapathi, Bala, Suresh Babu Raman, Gina Kertulis e Lena Ma. "Arsenic-resistant proteobacterium from the phyllosphere of arsenic-hyperaccumulating fern (Pteris vittata L.) reduces arsenate to arsenite". Canadian Journal of Microbiology 52, n. 7 (1 luglio 2006): 695–700. http://dx.doi.org/10.1139/w06-017.
Testo completoAbstract (sommario):
An arsenic-resistant bacterium, AsRB1, was isolated from the fronds of Pteris vittata grown in a site contaminated with copper chromium arsenate. The bacterium exhibited resistance to arsenate, arsenite, and antimony in the culture medium. AsRB1, like Pseudomonas putida, grew on MacConkey and xylose–lactose–desoxycholate agars and utilized citrate but, unlike P. putida, was positive for indole test and negative for oxidase test. A phylogenetic analysis of the 16S rRNA gene showed that AsRB1 is a proteobacterium of the beta subclass, related to Pseudomonas saccharophila and Variovorax paradoxus. Following an exogenous supply of arsenate, most arsenic occurred as arsenite in the medium and the cell extracts, suggesting reduction and extrusion of arsenic as the mechanism for arsenic resistance in AsRB1.Key words: arsenate reduction, arsenic bioremediation, Pseudomonas saccharophila, Variovorax paradoxus, Pteris vittala.
36
Harfoush, M., S. A. Mirbagheri, M. Ehteshami e S. Nejati. "Arsenic removal from drinking water using low-pressure nanofiltration under various operating conditions". Water Practice and Technology 13, n. 2 (1 giugno 2018): 295–302. http://dx.doi.org/10.2166/wpt.2018.042.
Testo completoAbstract (sommario):
Abstract Currently, one of the main environmental concerns is the toxicity caused by arsenic. Arsenic-polluted water can cause many human health problems including various cancerous diseases. In natural water, inorganic arsenic can be found in the forms of arsenite and arsenate, which have been found in several Iranian provinces – e.g., East Azerbaijan, Kurdistan, and the city of Bijar – in high concentrations. Modern nanofiltration (NF) technology enables a wide range of water resource pollutants to be controlled efficiently. In this study, in an attempt to enhance arsenic removal (both arsenite and arsenate) from drinking water using low pressure NF, operating conditions like arsenic concentration, the trans-membrane pressure applied, and a range of different temperatures have all been considered. The highest arsenate removal achieved was 94% with an initial concentration of 500 μg/L, at 7 bar pressure, and 28 °C. The highest arsenite removal was 90%, with an initial concentration of 100 μg/L, at 5 bar pressure, and also at 28 °C. Increasing the pressure had a positive effect on the removal of both species, however, increasing the temperature had negative impacts. It was always found that arsenate removal was better than arsenite removal.
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Duquesne, K., S. Lebrun, C. Casiot, O. Bruneel, J. C. Personné, M. Leblanc, F. Elbaz-Poulichet, G. Morin e V. Bonnefoy. "Immobilization of Arsenite and Ferric Iron by Acidithiobacillus ferrooxidans and Its Relevance to Acid Mine Drainage". Applied and Environmental Microbiology 69, n. 10 (ottobre 2003): 6165–73. http://dx.doi.org/10.1128/aem.69.10.6165-6173.2003.
Testo completoAbstract (sommario):
ABSTRACT Weathering of the As-rich pyrite-rich tailings of the abandoned mining site of Carnoulès (southeastern France) results in the formation of acid waters heavily loaded with arsenic. Dissolved arsenic present in the seepage waters precipitates within a few meters from the bottom of the tailing dam in the presence of microorganisms. An Acidithiobacillus ferrooxidans strain, referred to as CC1, was isolated from the effluents. This strain was able to remove arsenic from a defined synthetic medium only when grown on ferrous iron. This A. ferrooxidans strain did not oxidize arsenite to arsenate directly or indirectly. Strain CC1 precipitated arsenic unexpectedly as arsenite but not arsenate, with ferric iron produced by its energy metabolism. Furthermore, arsenite was almost not found adsorbed on jarosite but associated with a poorly ordered schwertmannite. Arsenate is known to efficiently precipitate with ferric iron and sulfate in the form of more or less ordered schwertmannite, depending on the sulfur-to-arsenic ratio. Our data demonstrate that the coprecipitation of arsenite with schwertmannite also appears as a potential mechanism of arsenite removal in heavily contaminated acid waters. The removal of arsenite by coprecipitation with ferric iron appears to be a common property of the A. ferrooxidans species, as such a feature was observed with one private and three collection strains, one of which was the type strain.
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Hutton, C., D. W. Bryce, W. Russeau, H. J. Glass, L. E. T. Jenkin, W. T. Corns e P. B. Stockwell. "Aqueous and solid-phase speciation of arsenic in Cornish soils". Mineralogical Magazine 69, n. 5 (ottobre 2005): 577–89. http://dx.doi.org/10.1180/0026461056950272.
Testo completoAbstract (sommario):
AbstractCornwall (UK) has suffered extensive arsenic contamination due to the historic mining and processing of mineral ores. Standard procedures for contaminated land risk assessment (DEFRA and Environment Agency, 2002a) are probably unworkable in Cornwall, with a very large number of sites classified as contaminated by arsenic. Methods of measuring the speciation and mobility of arsenic are essential for effective and rapid risk assessments of arsenic contamination.Three clusters of lysimeters were installed in three different areas of an arsenic-contaminated Cornish site. A novel phosphoric acid microwave extraction technique was applied to the soils removed from the lysimeter holes; HPLC-HG-AFS analysis showed the majority of solid-phase arsenic to be arsenate (AsV). Pore waters obtained from the lysimeters showed variable, relatively low levels of arsenite (AsIII) and arsenate (AsV) to be present (<1–129 μg l–1). Less toxic arsenate predominated in most pore waters, with the presence of minor amounts of arsenite suggesting heterogeneous redox conditions. Pore-water arsenic concentrations were strongly positively related to solid-phase arsenate concentrations.The use of techniques that assess the speciation of arsenic both in the solid and aqueous phases of a soil provides important information about the mobility of arsenic. The methodology presented in this paper may offer a novel basis for risk assessments of other contaminated sites.
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YAMAZAKI, H., K. ISHII, Y. TAKAHASHI, S. MATSUYAMA, Y. KIKUCHI, Ts AMARTAIVAN, T. YAMAGUCHI et al. "IDENTIFICATION OF OXIDATION STATES OF TRACE-LEVEL ARSENIC IN ENVIRONMENTAL WATER SAMPLES USING PIXE". International Journal of PIXE 15, n. 03n04 (gennaio 2005): 241–47. http://dx.doi.org/10.1142/s012908350500057x.
Testo completoAbstract (sommario):
An enhanced sample preparation method for PIXE analysis is described allowing to separate and concentrate arsenic ions of different oxidation states in water samples. Arsenate ions are separated from arsenite ions by co-precipitating into 10 ppm indium hydroxide colloids that are generated at pH 4.0 in a 25 ml solution containing 1 ppm phosphate ions and 25 ppm sulfate ions. Arsenite ions are oxidized to the pentavalent state with permanganate ions and adsorbed by indium hydroxide colloids generated afterwards in solution. The standard procedure for collecting the colloids adsorbing arsenic ions on Nuclepore filter of 0.2 μm pores is based on an investigation of the pH-dependence of the recovery of dissolved arsenic ions and the obtained standard calibration curve covers the concentration range from 1 to 100 ppb for arsenic ions. The prepared targets were examined for 5 to 10 minutes by 3 MeV proton beam (0.7-4 nA beam currents). The lower detection limit of arsenic in a 25 ml aquatic sample is 0.3 ppb for the arsenic-precipitated targets based on the 3σ error of background counts integrated over the FWHM of arsenic peak in the PIXE spectrum. This sample preparation technique was then applied to analyze concentrations and oxidation states of arsenic in a river basin where hot springs are located upstream being possible sources for releasing arsenic in the river.
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Ma, Mingsheng, e X. Chris Le. "Effect of arsenosugar ingestion on urinary arsenic speciation". Clinical Chemistry 44, n. 3 (1 marzo 1998): 539–50. http://dx.doi.org/10.1093/clinchem/44.3.539.
Testo completoAbstract (sommario):
Abstract We developed and evaluated a method for the determination of μg/L concentrations of individual arsenic species in urine samples. We have mainly studied arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA), and dimethylarsinic acid (DMAA) because these are the most commonly used biomarkers of exposure by the general population to inorganic arsenic and because of concerns over these arsenic species on their toxicity and carcinogenicity. We have also detected five unidentified urinary arsenic species resulting from the metabolism of arsenosugars. We combined ion pair liquid chromatography with on-line hydride generation and subsequent atomic fluorescence detection (HPLC/HGAFS). Detection limits, determined as three times the standard deviation of the baseline noise, are 0.8, 1.2, 0.7, and 1.0 μ/L arsenic for arsenite, arsenate, MMAA, and DMAA, respectively. These correspond to 16, 24, 14, and 20 pg of arsenic, respectively, for a 20-μL sample injected for analysis. The excellent detection limit enabled us to determine trace concentrations of arsenic species in urine samples from healthy subjects who did not have excess exposure to arsenic. There was no need for any sample pretreatment step. We used Standard Reference Materials, containing both normal and increased concentrations of arsenic, to validate the method. Interlaboratory studies with independent techniques also confirmed the results obtained with the HPLC/HGAFS method. We demonstrated an application of the method to the determination of arsenic species in urine samples after the ingestion of seaweed by four volunteers. We observed substantial increases of DMAA concentrations in the samples collected from the volunteers after the consumption of seaweed. The increase of urinary DMAA concentration is due to the metabolism of arsenosugars that are present in the seaweed. Our results suggest that the commonly used biomarkers of exposure to inorganic arsenic, based on the measurement of arsenite, arsenate, MMAA, and DMAA, are not reliable when arsenosugars are ingested from the diet.
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Khatun, Shamima, Moulima Maity, Hasina Perveen, Moumita Dash e Sandip Chattopadhyay. "Spirulina platensis ameliorates arsenic-mediated uterine damage and ovarian steroidogenic disorder". FACETS 3, n. 1 (1 ottobre 2018): 736–53. http://dx.doi.org/10.1139/facets-2017-0099.
Testo completoAbstract (sommario):
Novel, non-invasive, painless oral therapeutic agents are needed to replace the painful conventional treatment of arsenic-associated health hazards with metal chelators. Our aim was to examine the effect of spirulina ( Spirulina platensis ( Geitler, 1925 )) on arsenic-mediated uterine toxicity. Female Wistar rats were divided equally into four experimental treatment groups: control group, sodium arsenite group (1.0 mg/100 g body mass), spirulina placebo group (20 mg/100 g body mass), and sodium arsenite + spirulina group. In contrast with the control group, spectrophotometric and electrozymographic evaluation revealed that rats that ingested arsenic for 8 d showed significant diminution of the activities of superoxide dismutase, catalase, and peroxidase ( p < 0.001). Mutagenic uterine DNA breakage and tissue damage were prominent following arsenic consumption by the rats. Oral delivery of spirulina resulted in a significant amelioration of arsenic-induced adverse oxidative stress and genotoxic state of rats. A significant low-signaling ( p < 0.001) of gonadotropins and estradiol was also noted in the arsenic-treated rats, which was terminated by spirulina; this arsenic-primed adverse effect was significant ( p < 0.05, p < 0.01). The spirulina treatment mechanism could be associated with augmentation of the antioxidant defense system that protects the arsenic-mediated pathological state of the uterus.
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Miyashita, Shin-ichi, Shoko Fujiwara, Mikio Tsuzuki e Toshikazu Kaise. "Cyanobacteria produce arsenosugars". Environmental Chemistry 9, n. 5 (2012): 474. http://dx.doi.org/10.1071/en12061.
Testo completoAbstract (sommario):
Environmental contextAlthough arsenic is known to accumulate in both marine and freshwater ecosystems, the pathways by which arsenic is accumulated and transferred in freshwater systems are reasonably unknown. This study revealed that freshwater cyanobacteria have the ability to produce arsenosugars from inorganic arsenic compounds. The findings suggest that not only algae, but cyanobacteria, play an important role in the arsenic cycle of aquatic ecosystems. AbstractMetabolic processes of incorporated arsenate in axenic cultures of the freshwater cyanobacteria Synechocystis sp. PCC 6803 and Nostoc (Anabaena) sp. PCC 7120 were examined. Analyses of arsenic compounds in cyanobacterial extracts using a high-performance liquid chromatography–inductively coupled plasma mass spectrometry system showed that both strains have an ability to biotransform arsenate into oxo-arsenosugar-glycerol within 20 min through (1) reduction of incorporated arsenate to arsenite and (2) methylation of produced arsenite to dimethylarsinic acid by methylarsonic acid as a possible intermediate product. In addition, Synechocystis sp. PCC 6803 cells are able to biosynthesise oxo-arsenosugar-phosphate from incorporated arsenate. These findings suggest that arsenosugar formation as well as arsenic methylation in cyanobacteria possibly play a significant role in the global arsenic cycle.
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Shakya, Sangita, e B. Pradhan. "Isolation and Characterization of Arsenic Resistant Pseudomonas Stutzeri ASP3 for its Potential in Arsenic Resistance and Removal". Kathmandu University Journal of Science, Engineering and Technology 9, n. 1 (31 luglio 2013): 48–59. http://dx.doi.org/10.3126/kuset.v9i1.63842.
Testo completoAbstract (sommario):
Inorganic arsenic both arsenite As (III) and arsenate As (V) constitute the highest toxicological risk associated with arsenic in drinking water. Novel methods are in demand for its removal from water, especially in rural areas. For this purpose, the potential of different microbes in arsenic resistance and removal from water has gained interests worldwide. This study investigates the arsenic resistance and removal capacity of a bacterial strain isolated from arsenic enriched water of Rautahat district in Nepal. The concentration of arsenic was by hydride generation atomic absorption spectrophotometer. The isolated bacterium showed high resistance to sodium arsenate up to 4,680.15 mg/l and sodium arsenite up to 649.55 mg/l. The bacterium also conferred multiple heavy metal resistance to zinc chloride (136.28 mg/l), copper sulphate (249.68 mg/l), mercuric chloride (5.43 mg/l) and silver nitrate (3.39 mg/l). The growth rate calculated in the presence of 129.01 mg/l of sodium arsenite was 0.35 h-1 with doubling time of 1.96 h. The strain showed growth in the range of 25–45 °C (optimum 30-35 °C), pH 6 – 9 (optimum 7.5-8.5) and tolerated up to 10% of NaCl. The PCR-based 16S rDNA sequence analysis revealed that the isolated As resistant bacterium is a close relative to P. stutzeri (99%) with 30 hits. The bacterium removed 82.97 % of As (V) and 49.4% of As (III) from culture medium amended with 200 mg/l sodium arsenate and 74.92 mg/l of sodium arsenite respectively.
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Tahir, M. A., H. Rasheed e A. Malana. "Method development for arsenic analysis by modification in spectrophotometric technique". Drinking Water Engineering and Science 5, n. 1 (4 gennaio 2012): 1–8. http://dx.doi.org/10.5194/dwes-5-1-2012.
Testo completoAbstract (sommario):
Abstract. Arsenic is a non-metallic constituent, present naturally in groundwater due to some minerals and rocks. Arsenic is not geologically uncommon and occurs in natural water as arsenate and arsenite. Additionally, arsenic may occur from industrial discharges or insecticide application. World Health Organization (WHO) and Pakistan Standard Quality Control Authority have recommended a permissible limit of 10 ppb for arsenic in drinking water. Arsenic at lower concentrations can be determined in water by using high tech instruments like the Atomic Absorption Spectrometer (hydride generation). Because arsenic concentration at low limits of 1 ppb can not be determined easily with simple spectrophotometric technique, the spectrophotometric technique using silver diethyldithiocarbamate was modified to achieve better results, up to the extent of 1 ppb arsenic concentration.
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Tahir, M. A., H. Rasheed e A. Malana. "Method development for arsenic analysis by modification in spectrphotometric technique". Drinking Water Engineering and Science Discussions 1, n. 2 (22 agosto 2008): 135–54. http://dx.doi.org/10.5194/dwesd-1-135-2008.
Testo completoAbstract (sommario):
Abstract. Arsenic is a non-metallic constituent, present naturally in groundwater due to some minerals and rocks. Arsenic is not geologically uncommon and occurs in natural water as arsenate and arsenite. Additionally, arsenic may occur from industrial discharges or insecticide application. World Health Organization (WHO) and Pakistan Standard Quality Control Authority have recommended a permissible limit of 10 ppb for arsenic in drinking water. The arsenic at lower concentrations can be determined in water by using high tech instruments like Atomic Absorption Spectrometer (hydride generation). The arsenic concentration at low limits of 1 ppb could not be determined easily with simple spectrophotometric technique. Therefore, Spectrphotometric technique using the silver diethyldithiocarbamate was modified to achieve the better results, up to the extent of 1 ppb arsenic concentration.
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Sinha, B., e K. Bhattacharyya. "Arsenic speciation in rice and risk assessment of inorganic arsenic from Ghentugachhi village of Chakdaha block, Nadia, West Bengal, India". Oryza-An International Journal on Rice 57, n. 2 (30 giugno 2020): 85–93. http://dx.doi.org/10.35709/ory.2020.57.2.1.
Testo completoAbstract (sommario):
The purpose of the present study was to assess arsenic (As) speciation in rice from West Bengal, India, in order to improve understanding of the health risk posed by arsenic in Indian rice. Rice is a potentially important route of human exposure to arsenic, especially in populations with rice-based diets. However, arsenic toxicity varies greatly with species. Determination of arsenic (As) species in rice is necessary because inorganic As species are more toxic than organic As. Total arsenic was determined by inductively coupled plasma mass spectrometry; arsenite, arsenate, monomethylarsonic acid, and dimethyarsinic acid were quantified by high-performance liquid chromatography- inductively coupled plasma mass spectrometry. The analysis of a rice flour certified reference material (SRM-1568-a) were evaluated for quality assurance. The use of 2M TFA for extraction with an isocratic mobile phase was optimized for extraction and employed for arsenic speciation in rice. The extraction method showed a high recovery of arsenic. Most of the As species in rice were noticed to be inorganic [Arsenite (As-III), Arsenate As-V]. It appeared very clear from the present study that inorganic arsenic shared maximum arsenic load in rice straw while in grains it is considerably low. As species recovered from rice grain and straw are principally As-III and As-V with a little share of DMA and almost non-detectable MMA and As-B. The order of As species in rice grain revealed in this study were As-III (54.5-65.4 %)>As-V(21.2-28.3%)>DMA(5.2%).
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Coryell, Michael, Barbara A. Roggenbeck e Seth T. Walk. "The Human Gut Microbiome’s Influence on Arsenic Toxicity". Current Pharmacology Reports 5, n. 6 (25 novembre 2019): 491–504. http://dx.doi.org/10.1007/s40495-019-00206-4.
Testo completoAbstract (sommario):
Abstract Purpose of Review Arsenic exposure is a public health concern of global proportions with a high degree of interindividual variability in pathologic outcomes. Arsenic metabolism is a key factor underlying toxicity, and the primary purpose of this review is to summarize recent discoveries concerning the influence of the human gut microbiome on the metabolism, bioavailability, and toxicity of ingested arsenic. We review and discuss the current state of knowledge along with relevant methodologies for studying these phenomena. Recent Findings Bacteria in the human gut can biochemically transform arsenic-containing compounds (arsenicals). Recent publications utilizing culture-based approaches combined with analytical biochemistry and molecular genetics have helped identify several arsenical transformations by bacteria that are at least possible in the human gut and are likely to mediate arsenic toxicity to the host. Other studies that directly incubate stool samples in vitro also demonstrate the gut microbiome’s potential to alter arsenic speciation and bioavailability. In vivo disruption or elimination of the microbiome has been shown to influence toxicity and body burden of arsenic through altered excretion and biotransformation of arsenicals. Currently, few clinical or epidemiological studies have investigated relationships between the gut microbiome and arsenic-related health outcomes in humans, although current evidence provides strong rationale for this research in the future. Summary The human gut microbiome can metabolize arsenic and influence arsenical oxidation state, methylation status, thiolation status, bioavailability, and excretion. We discuss the strength of current evidence and propose that the microbiome be considered in future epidemiologic and toxicologic studies of human arsenic exposure.
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Ambasta, S. K., S. Kumari e Uk Sinha. "ANTICLASTOGENICITY OF TINOSPORA CORDIFOLIA STEM EXTRACT AGAINST ARSENIC GENOTOXICITY IN MUS MUSCULUS BONE MARROW ERYTHROCYTES USING MICRONUCLEUS ASSAY". International Journal of Pharmacy and Pharmaceutical Sciences 9, n. 10 (2 ottobre 2017): 260. http://dx.doi.org/10.22159/ijpps.2017v9i10.20249.
Testo completoAbstract (sommario):
Objective: The study was aimed to evaluate anticlastogenic potential of ethanolic extract of T. cordifolia stem against arsenic induced genotoxicity.Methods: In the experiment twenty five animals were taken and divided into five groups and each group contain five animals. Group 01(control) and fed on tap water while the rest four (02, 03, 04, 05) groups were treated with 4 mg/kg body weight, per orally sodium arsenite for 8 w. Sodium arsenite pretreated groups 04 and 05 were followed by dose of 80 mg/kg body weight of 5% ethanolic solution of the test plant stem extract for a next 8 w. Bone marrow cells were collected in Hank’s Balanced Salt Solution and smeared on a slide followed by double staining (Giemsa and Harris hematoxylin).Results: High index of micronucleus frequency was observed in the groups 02 and 03 in contrast to group 01(control) while micronucleus frequency dramatically reduced in 04 and 05 groups. The mean number of micronucleus scored/2000 cell was found to be 2.6, 19.2, 20.2, 7 and 6.8 in group 01, 02, 03, 04, 05 respectively. Arsenic treated mice (03) showed remarkable increase (p≤0.001) in micronucleus frequency when compared to the corresponding values for control group (01). The percentage micronucleus frequency (mean and standard deviation) was markedly decreased (p≤ 0.019) when group 04 was compared with arsenic treated animals (group 02) and (p≤ 0.001) while group 05 was compared with arsenic treated animals (group 03) for their corresponding values.Conclusion: The findings of this study have shown that T. cordifolia may be used as a preventive herbal drug against chemical or arsenical toxicity which leads to damage of genetic materials.
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Wang, Gejiao, Sean P. Kennedy, Sabeena Fasiludeen, Christopher Rensing e Shiladitya DasSarma. "Arsenic Resistance in Halobacterium sp. Strain NRC-1 Examined by Using an Improved Gene Knockout System". Journal of Bacteriology 186, n. 10 (15 maggio 2004): 3187–94. http://dx.doi.org/10.1128/jb.186.10.3187-3194.2004.
Testo completoAbstract (sommario):
ABSTRACT The genome sequence of Halobacterium sp. strain NRC-1 encodes genes homologous to those responsible for conferring resistance to arsenic. These genes occur on both the large extrachromosomal replicon pNRC100 (arsADRC and arsR2M) and on the chromosome (arsB). We studied the role of these ars genes in arsenic resistance genetically by construction of gene knockouts. Deletion of the arsADRC gene cluster in a Halobacterium NRC-1 Δura3 strain resulted in increased sensitivity to arsenite and antimonite but not arsenate. In contrast, knockout of the chromosomal arsB gene did not show significantly increased sensitivity to arsenite or arsenate. We also found that knockout of the arsM gene produced sensitivity to arsenite, suggesting a second novel mechanism of arsenic resistance involving a putative arsenite(III)-methyltransferase. These results indicate that Halobacterium sp. strain NRC-1 contains an arsenite and antimonite extrusion system with significant differences from bacterial counterparts. Deletion analysis was facilitated by an improved method for gene knockouts/replacements in Halobacterium that relies on both selection and counterselection of ura3 using a uracil dropout medium and 5-fluoroorotic acid. The arsenite and antimonite resistance elements were shown to be regulated, with resistance to arsenic in the wild type inducible by exposure to a sublethal concentration of the metal. Northern hybridization and reverse transcription-PCR analyses showed that arsA, arsD, arsR, arsM, arsC, and arsB, but not arsR2, are inducible by arsenite and antimonite. We discuss novel aspects of arsenic resistance in this halophilic archaeon and technical improvements in our capability for gene knockouts in the genome.
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Lin, Lin, Teresa M. Stringfield, Xianglin Shi e Yan Chen. "Arsenite induces a cell stress-response gene, RTP801, through reactive oxygen species and transcription factors Elk-1 and CCAAT/enhancer-binding protein". Biochemical Journal 392, n. 1 (8 novembre 2005): 93–102. http://dx.doi.org/10.1042/bj20050553.
Testo completoAbstract (sommario):
RTP801 is a newly discovered stress-response gene that is induced by hypoxia and other cell stress signals. Arsenic is a heavy metal that is linked to carcinogenesis in humans. Here, we investigated the mechanism by which arsenic induces RTP801 transcription. In HaCaT human keratinocytes, arsenite was able to induce a rapid rise in the RTP801 mRNA level. Correspondingly, arsenite treatment was capable of stimulating a 2.5 kb human RTP801 promoter. Such a stimulatory effect was inhibited by co-expression of superoxide dismutase or glutathione peroxidase, and was abrogated by N-acetylcysteine, implying that ROS (reactive oxygen species) were involved in transcriptional regulation of the RTP801 gene. A series of deletion studies with the promoter revealed a critical arsenic-responsive region between −1057 and −981 bp of the promoter. Point mutations of the putative Elk-1 site and the C/EBP (CCAAT/enhancer-binding protein) site within this region were able to reduce the stimulatory effect of arsenite, indicating that Elk-1 and C/EBP are involved in transcriptional regulation of the RTP801 gene by arsenite. Furthermore, a gel mobility-shift assay demonstrated that arsenite was able to mount the rapid formation of a protein complex that bound the arsenic-responsive region as well as the C/EBP-containing sequence. The arsenite stimulation on RTP801 transcription was partly mediated by the ERK (extracellular-signal-regulated kinase) pathway, since the effect of RTP801 was inhibited by a selective ERK inhibitor. In addition, overexpression of Elk-1 and C/EBPβ was able to elevate the promoter activity. Therefore these studies indicate that RTP801 is a transcriptional target of arsenic in human keratinocytes, and that arsenic and ROS production are linked to Elk-1 and C/EBP in the transcriptional control.