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Arsenic Hazard ID

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The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

A periplasmic arsenite-binding protein involved in regulating arsenite oxidation

Authors: Liu, G; Liu, M; Kim, E-H; Matty, WS; Bothner, B; Lei, B; Rensing, C; Wang, G; McDermott, TR (In Press) Environmental Microbiology. HERO ID: 1003591

[Less] Arsenic (As) is the most common toxic element in the environment, ranking first on the Superfund List . . . [More] Arsenic (As) is the most common toxic element in the environment, ranking first on the Superfund List of Hazardous Substances. Microbial redox transformations are the principal drivers of As chemical speciation, which in turn dictates As mobility and toxicity. Consequently, in order to manage or remediate environmental As, land managers need to understand how and why microorganisms react to As. Studies have demonstrated a two-component signal transduction system comprised of AioS (sensor kinase) and AioR (response regulator) is involved in regulating microbial AsIII oxidation, with the AsIII oxidase structural genes aioB and aioA being upregulated by AsIII. However, it is not known whether AsIII is first detected directly by AioS or by an intermediate. Herein we demonstrate the essential role of a periplasmic AsIII-binding protein encoded by aioX, which is upregulated by AsIII. An ΔaioX mutant is defective for upregulation of the aioBA genes and consequently AsIII oxidation. Purified AioX expressed without its TAT-type signal peptide behaves as a monomer (MW 32 kDa), and Western blots show AioX to be exclusively associated with the cytoplasmic membrane. AioX binds AsIII with a K(D) of 2.4 µM AsIII; however, mutating a conserved Cys108 to either alanine or serine resulted in lack of AsIII binding, lack of aioBA induction, and correlated with a negative AsIII oxidation phenotype. The discovery and characterization of AioX illustrates a novel AsIII sensing mechanism that appears to be used in a range of bacteria and also provides one of the first examples of a bacterial signal anchor protein.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Transport routes of metalloids into and out of the cell: A review of the current knowledge

Authors: Zangi, R; Filella, M (In Press) Chemico-Biological Interactions. [Review] HERO ID: 1015719

[Less] Except for their extra- and intra-cellular interfaces, cell membranes are hydrophobic and inhibit the . . . [More] Except for their extra- and intra-cellular interfaces, cell membranes are hydrophobic and inhibit the transport of hydrophilic molecules. Metalloids in aqueous solutions form chemical species with oxygen and hydroxyl groups and, therefore, exist as hydrophilic neutral polar solutes or as hydrophilic anions. This characteristic of metalloids introduces a large barrier for their passage through the cell membrane via unaided diffusion. The necessity for an uptake mechanism for metalloids arises from the requirement of these species for the maintenance of life, such as the need of boron for plant cells. Conversely, the transport of these species out of the cell is necessary because some metalloids are toxic, such as arsenic and antimony, and their entrance into the cell is undesirable. The undesired uptake of these toxic species is possible via pathways designed for the uptake of other structurally and chemically similar essential compounds. Therefore, the extrusion of arsenic and antimony out of the cell is an example of a detoxification mechanism. As a consequence of the hydrophobic character of the cell membrane in all living systems, the main route for the uptake and efflux of metalloids is facilitated by transmembrane proteins, driven either by concentration gradients or by energy-fueled pumps. However, metalloids forming or embedded in nano-sized particles escape the need to cross the cell membrane because these particles can be taken into the cell by endocytosis. Here, we review the uptake and efflux pathways of boron, silicon, arsenic, and antimony through the cell membranes of different organisms and the protein channels involved in these processes. In particular, passive diffusion via aquaglyceroporins, active transport via primary and secondary ion pumps, extrusion into vacuoles of metalloid-thiol conjugates via ATP-binding cassette, the efflux of methylated metalloids, and endocytosis are summarized.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Structure-function alteration of hemoglobin in arsenicosis patients: A probable pathway to exert toxicity

Authors: Mondal, B; Chatterjee, D; Bhattacharyya, M (In Press) Journal of Applied Toxicology. HERO ID: 711038

[Less] Chronic arsenicosis, a major public health concern in India and Bangladesh, is mainly caused by ingestion . . . [More] Chronic arsenicosis, a major public health concern in India and Bangladesh, is mainly caused by ingestion of arsenic (As) contaminated ground water. Although this problem has been studied extensively, the mechanism of toxicity remains unknown. This paper investigates the process of trivalent arsenicals binding to hemoglobin (Hb) in chronic arsenicosis patients and consequent modification in the structure-function activity of Hb. In this work peroxidase activity, thermal denaturation profile, oxygen releasing capacity and hydrodynamic diameter have been evaluated for the Hb collected from subjects suffering with chronic arsenicosis. Increased peroxidative activity suggests altered oxidative status of Hb in the diseased state. The thermal denaturation profile indicates the Hb molecule to be more susceptible to unfolding in the pathologic state. The enhanced oxygen releasing capacity and significant reduction in hydrodynamic diameter of Hb is also observed in the diseased condition, suggesting conformational alterations in the Hb molecule. Finally, trivalent arsenic is found to bind with freshly isolated Hb from arsenicosis patients, binding affinity constant being 0.256 μM(-1) . The binding is positively cooperative with a Hill coefficient of +2.961 and isosbestic points at specific wavelengths. Thus, our work explores the structure-function property of Hb in chronic arsenicosis subjects and reveals that the molecule is modified in such a way that comparatively weak binding with oxygen and strong binding with arsenic occur simultaneously. This association may play a crucial role in exerting the pathway for arsenic toxicity. Copyright © 2011 John Wiley & Sons, Ltd.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Arsenic induced progesterone production in a caspase-3 dependent manner and changed redox status in preovulatory granulosa cells

Authors: Yuan, XH; Lu, CL; Yao, N; An, LS; Yang, BQ; Zhang, CL; Ma, X (In Press) Journal of Cellular Physiology. HERO ID: 710825

[Less] Arsenic contamination is a principal environmental health threat throughout the world. However, little . . . [More] Arsenic contamination is a principal environmental health threat throughout the world. However, little is known about the effect of arsenic on steroidogenesis in granulosa cells (GCs). We found that the treatment of preovulatory GCs with arsenite stimulated progesterone production. A significant increase in serum level of progesterone was observed in female Sprague-Dawley rats following arsenite treatment at a dose of 10 mg/L/rat/day for 7 days. Further experiments demonstrated that arsenite treatment did not change the level of intracellular cAMP or phosphorylated ERK1/2 in preovulatory GCs; however, progesterone production was significantly decreased when cAMP-dependent protein kinase (PKA) or ERK1/2 pathway was inhibited. This implied that the effect of arsenite on progesterone production may require cAMP/PKA and ERK1/2 signaling but not depend on them. Furthermore, we found that arsenite decreased intracellular reactive oxygen species (ROS) but increased the antioxidant glutathione (GSH) levels and mitochondrial membrane potential (ΔΨm) in parallel to the changes in progesterone production. Progesterone antagonist blocked the arsenic-stimulated increase of GSH levels. Arsenite treatment induced caspase-3 activation, although no apoptosis was observed. Inhibition of caspase-3 activity significantly decreased progesterone production stimulated by arsenite or follicle stimulating hormone (FSH). GSH depletion with buthionine sulfoximine (BSO) led to cell apoptosis in response to arsenite treatment. Collectively, this study demonstrated for the first time that arsenite stimulates progesterone production through cleaved/active caspase-3 dependent pathway, and the increase of GSH level promoted by progesterone production may protect GCs against apoptosis and maintain the steroidogenesis of GCs in response to arsenite treatment. © 2011 Wiley Periodicals, Inc.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

JNK dependent Stat3 phosphorylation contributes to Akt activation in response to arsenic exposure

Authors: Liu, J; Chen, B; Lu, Y; Guan, Y; Chen, F (In Press) Toxicological Sciences. HERO ID: 1244046

[Less] Environmental exposure to arsenic, especially the trivalent inorganic form (As3+), has been linked to . . . [More] Environmental exposure to arsenic, especially the trivalent inorganic form (As3+), has been linked to human cancers in addition to a number of other diseases including skin lesions, cardiovascular disorders, neuropathy, and internal organ injury. In the present study, we describe a novel signaling axis of the c-Jun NH2 kinase (JNK) and signal transducer and activator of transcription 3 (Stat3) and its involvement in As3+-induced Akt activation in human bronchial epithelial cells. As3+ activates JNK and induces phoshporylation of the Stat3 at serine 727 (S727) in a dose- and time-dependent manner, which occurred concomitantly with Akt activation. Disruption of the JNK signaling pathway by treatment with the JNK inhibitor SP600125, siRNA knockdown of JNK, or genetic deficiency of the JNK1 or JNK2 gene abrogated As3+-induced S727 phosphorylation of Stat3, Akt activation, and the consequent release of vascular endothelial growth factor (VEGF) and migration of the cells. Similarly, pretreatment of the cells with Stat3 inhibitor or Stat3 siRNA prevented Akt activation and VEGF release from the cells in response to As3+ treatment. Taken together, these data revealed a new signaling mechanism that might be pivotal in As3+-induced malignant transformation of the cells by linking the key stress signaling pathway, JNK, to the activation of Stat3 and the carcinogenic kinase, Akt.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Arsenic-induced health crisis in peri-urban Moyna and Ardebok villages, West Bengal, India: an exposure assessment study

Authors: Maity, JP; Nath, B; Kar, S; Chen, CY; Banerjee, S; Jean, JS; Liu, MY; Centeno, JA; Bhattacharya, P; Chang, CL; Santra, SC (In Press) Environmental Geochemistry and Health. HERO ID: 1070319

[Less] Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people . . . [More] Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people worldwide. This study aimed to determine the degree of severity of As exposure from drinking water in peri-urban Moyna and Ardebok villages, West Bengal, India. Arsenic concentrations in hair, nail and urine samp les of the individuals were determined. Arsenical dermatosis, keratosis and melanosis were investigated through medical evaluation. We have evaluated the association between As exposure from drinking water, and keratosis and melanosis outcomes. The results showed that 82.7 % of the sampled tube wells contain As concentrations above 10 μg/L, while 57.7 % contain As concentrations above 50 μg/L. The hair, nail and urine As concentrations were positively correlated with As concentrations in drinking water. In our study population, we observed a strong association between As concentrations ranging 51-99 μg/L and keratosis and melanosis outcomes, although the probability decreases at higher concentration ranges perhaps due to switching away from the use of As-contaminated tube wells for drinking and cooking purposes. High As concentrations in hair, nail and urine were observed to be associated with the age of the study population. The level of As concentrations in hair, nail and urine samples of the study population indicated the degree of severity of As exposure in the study region.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Differential modulation of aryl hydrocarbon receptor regulated enzymes by arsenite in the kidney, lung, and heart of C57BL/6 mice

Authors: Anwar-Mohamed, A; Abdelhamid, G; Amara, IEA; El-Kadi, AOS (In Press) Archives of Toxicology. HERO ID: 1070382

[Less] During the last couple of decades, efforts have been made to study the toxic effects of individual aryl . . . [More] During the last couple of decades, efforts have been made to study the toxic effects of individual aryl hydrocarbon receptors (AhR) ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or heavy metals typified by arsenic As(III). However, little is known about the combined toxic effects of TCDD and As(III) in vivo. Previous reports from our laboratory and others have demonstrated that As(III), by itself or in the presence of AhR ligands, such as TCDD, is capable of differentially altering the expression of various phase I and phase II AhR-regulated genes in in vitro systems. Thus, the objective of the current study was to investigate whether or not similar effects would occur at the in vivo level. Therefore, we examined the effect of exposure to As(III) (12.5 mg/kg) in the absence and presence of TCDD (15 μg/kg) on the AhR-regulated genes using C57Bl/6 mice. Our results demonstrated that As(III) alone inhibited Cyp1a1 and Cyp1a2 in the kidney, while it induced their levels in the lung and did not affect their mRNA levels in the heart. As(III) also induced Nqo1 and Gsta1 in all tested tissues. Upon co-exposure to As(III) and TCDD, As(III) inhibited the TCDD-mediated induction of Cyp1a1 in the kidney and heart, Cyp1a2 in the kidney and heart, while it potentiated TCDD-mediated induction of Cyp1a1 in the lung, and Nqo1 and Gsta1 in the kidney and lung. In conclusion, the present study demonstrates for the first time that As(III) modulates constitutive and TCDD-induced AhR-regulated genes in a time-, tissue-, and AhR-regulated enzyme-specific manner.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Structural and Functional Consequences of Phosphate-Arsenate Substitutions in Selected Nucleotides: DNA, RNA, and ATP

Authors: Xu, Y; Ma, B; Nussinov, R (In Press) Journal of Physical Chemistry B. HERO ID: 1070446

[Less] A recent finding of a bacterial strain (GFAJ-1) that can rely on arsenic instead of phosphorus raised . . . [More] A recent finding of a bacterial strain (GFAJ-1) that can rely on arsenic instead of phosphorus raised the questions of if and how arsenate can replace phosphate in biomolecules that are essential to sustain cell life. Apart from questions related to chemical stability, there are those of the structural and functional consequences of phosphate-arsenate substitutions in vital nucleotides in GFAJ1-like cells. In this study we selected three types of molecules (ATP/ADP as energy source and replication regulation; DNA-protein complexes for DNA replication and transcription initiation; and a tRNA-protein complex and ribosome for protein synthesis) to computationally probe if arsenate nucleotides can retain the structural and functional features of phosphate nucleotides. Hydrolysis of adenosine triarsenate provides 2-3 kcal/mol less energy than ATP hydrolysis. Arsenate DNA/RNA interacts with proteins slightly less strongly than phosphate DNA/RNA, mainly due to the weaker electrostatic interactions of arsenate. We observed that the weaker arsenate RNA-protein interactions may hamper rRNA assembly into a functional ribosome. We further compared the experimental EXAFS spectra of the arsenic bacteria with theoretical EXAFS spectra for arsenate DNA and rRNA. Our results demonstrate that while it is possible that dried GFAJ-1 cells contain linear arsenate DNA, the arsenate 70S ribosome does not contribute to the main arsenate depository in the GFAJ-1 cell. Our study indicates that evolution has optimized the inter-relationship between proteins and DNA/RNA, which requires overall changes at the molecular and systems biology levels when replacing phosphate by arsenate.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Buffalo (Bubalus bubalis) epiphyseal proteins counteract arsenic-induced oxidative stress in brain, heart, and liver of female rats

Authors: Bharti, VK; Srivastava, RS; Sharma, B; Malik, JK (In Press) Biological Trace Element Research. HERO ID: 1022015

[Less] Arsenic (As) toxicity through induction of oxidative stress is a well-known mechanism of organ toxicity. . . . [More] Arsenic (As) toxicity through induction of oxidative stress is a well-known mechanism of organ toxicity. To address this problem, buffalo epiphyseal proteins (BEP, at 100 μg/kg BW, i.p. for 28 days) were administered intraperitoneally to female Wistar rats exposed to As (100 ppm sodium arsenite via drinking water for 28 days). Arsenic exposure resulted in marked elevation in lipid peroxidation in brain, cardiac, and hepatic tissues, whereas significant (p < 0.05) adverse change in catalase, superoxide dismutase, glutathione reductase, glutathione peroxidase, and reduced glutathione level were observed in cardiac, hepatic, and brain tissues of As-administered animals. BEP significantly (p < 0.05) counteracted all the adverse changes in antioxidant defense system brought about by As administration. Based on these results, we consider BEP as a potent antioxidant to be used for protection from arsenic-induced oxidative stress related damage of vital organs.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Sodium arsenite-induced abnormalities in expressions of Caveolin-1, eNOS, IKKβ, and COX-2 in SV-40 immortalized human uroepithelial cells and in urothelial carcinomas

Authors: Liu, X-P; Huang, Y-C; Hung, W-C; Chen, W-T; Yu, H-S; Chai, C-Y (In Press) Toxicology In Vitro. HERO ID: 1255519

[Less] Arsenic, a known human carcinogen, is found throughout the crust of the earth. Prolonged arsenic exposure . . . [More] Arsenic, a known human carcinogen, is found throughout the crust of the earth. Prolonged arsenic exposure is a known cause of urothelial carcinoma (UC) and blackfoot disease (BFD). The aim of this study was to determine the effect of sodium arsenite on Caveolin-1 and downstream signaling molecules (eNOS, IKKβ and COX-2) expression in human urothelial cells (SV-HUC-1). Immunohistochemical (IHC) staining of Caveolin-1, eNOS, IKKβ, and COX-2 was also compared between UC patients from endemic and non-endemic areas of BFD in Taiwan. Immunocytochemical staining and Western blotting results revealed increased expression of Caveolin-1, IKKβ, and COX-2 but decreased eNOS in SV-HUC-1 cells treated with low concentration of arsenite. Additionally, MEK inhibitor (U0126) significantly attenuated arsenite-induced expression of Caveolin-1, IKKβ and COX-2 while reducing eNOS expression. The IHC staining of UCs revealed that expressions of Caveolin-1, IKKβ, and COX-2 were significantly higher in patients from endemic areas of BFD compared to patients from non-endemic areas (p=0.011, p=0.002, p=0.0001) whereas eNOS was significantly lower (p=0.0001). The correlation observed between Caveolin-1 and downstream signaling molecule expression may be an important mechanism of arsenic-induced urothelial carcinogenesis.