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1.
Comprehensive analysis of the metabolomic characteristics on the health lesions induced by chronic arsenic exposure: A metabolomics study.
Jia, C, Wei, Y, Lan, Y, Hou, X, Zuo, J, Wang, T, Li, J, Guan, X, Yang, H, Mao, G
International journal of hygiene and environmental health. 2019;(3):434-445
Abstract
Early detection of the health lesions induced by chronic arsenic exposure (HLICAE) are crucial to prevent permanent arsenic-induced damage. If HLICAE can be identified in time, appropriate preventive and therapeutic measures may be provided without various avoidable lesions. The present study aims to assess the probability of HLICAE early recognition with metabolomics. Applying a case-control study, 94 participants with HLICAE (cases) and other 94 subjects without HLICAE (controls) were matched with gender and age (±1 year), coming from a previous chronic arsenic exposure cohort. Serum metabolomic profiles were assessed by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and analyzed with univariate and multivariate statistics. A total of 210 and 364 features were detected in positive and negative ion modes (ESI+/ESI-), respectively. The altered metabolic pathways included lipid and amino acid metabolisms. 28 metabolomics-based biomarkers were significantly associated with HLICAE and provided areas under the curve (AUC, 95% confidence interval) of 0.898 (0.836, 0.960) and 0.908 (0.855, 0.960) in the discovery phase, 78.6% and 86.4% of positive predictive values in the validation phase, in distinguishing HLICAE from controls in ESI+/ESI-, respectively. This study provides novel insights on mechanisms of health effects probably induced by chronic arsenic exposure, and these biomarkers may be applied in HLICAE early detection.
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2.
Biological As(III) oxidation in biofilters by using native groundwater microorganisms.
Crognale, S, Casentini, B, Amalfitano, S, Fazi, S, Petruccioli, M, Rossetti, S
The Science of the total environment. 2019;(Pt 1):93-102
Abstract
Arsenic (As) contamination in drinking water represents a worldwide threat to human health. During last decades, the exploitation of microbial As-transformations has been proposed for bioremediation applications. Among biological methods for As-contaminated water treatment, microbial As(III)-oxidation is one of the most promising approaches since it can be coupled to commonly used adsorption removal technologies, without requiring the addition of chemicals and producing toxic by-products. Despite the As(III) oxidation capability has been described in several bacterial pure or enrichment cultures, very little is known about the real potentialities of this process when mixed microbial communities, naturally occurring in As contaminated waters, are used. This study highlighted the contribution of native groundwater bacteria to As(III)-oxidation in biofilters, under conditions suitable for a household-scale treatment system. This work elucidated the influence of a variety of experimental conditions (i.e., various filling materials, flow rates, As(III) inflow concentration, As(III):As(V) ratio, filter volumes) on the microbially-mediated As(III)-oxidation process in terms of oxidation efficiency and rate. The highest oxidation efficiencies (up to 90% in 3 h) were found on coarse sand biofilters treating total initial As concentration of 100 μg L-1. The detailed microbial characterization of the As(III) oxidizing biofilms revealed the occurrence of several OTUs affiliated with families known to oxidize As(III) (e.g., Burkholderiaceae, Comamonadaceae, Rhodobacteraceae, Xanthomonadaceae). Furthermore, As-related functional genes increased in biofilter systems in line with the observed oxidative performances.
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3.
Micronucleus assay for monitoring the genotoxic effects of arsenic in human populations: A systematic review of the literature and meta-analysis.
Dong, J, Wang, JQ, Qian, Q, Li, GC, Yang, DQ, Jiang, C
Mutation research. Reviews in mutation research. 2019;:1-10
Abstract
The micronucleus (MN) assay has been used to determine the potential genotoxic effects in human populations exposed to arsenic. Some of these studies found an increase in MN frequency among exposed individuals, but others found no increase or inconclusive results. Thus, the main purpose of this current study was to investigate whether MN can be used as a biomarker for the arsenic exposure, as well as whether or not the different cell types that have been used to monitor MN frequency differ in their sensitivity to upon arsenic exposure. A systematic literature review was conducted followed by a meta-analysis. The review identified 25 useful studies with data from 3232 exposed individuals (15 studies assaying lymphocytes, 16 assaying buccal cells, and 9 assaying urothelial cells), with 18 studies measuring drinking water exposure, 5 measuring occupational exposure, one measuring coal burning, and one measuring dietary exposure. The meta-analysis indicated that the overall estimates of Mean Ratio (MR, defined as the mean value of the response in the exposed group divided by the mean value of the response in the reference group) were 2.95 (95% confidence interval (CI): 2.00 to 4.35), 2.36 (95% CI: 1.77 to 3.15), and 2.82 (95% CI: 1.86 to 4.28) for MN assays conducted with lymphocytes, buccal cells, and urothelial cells in the MN assay, respectively. Subgroup analysis showed that when the exposure method was drinking water, the MN frequencies increased significantly in lymphocytes (MR = 3.59, 95% CI: 2.30 to 5.60), in buccal cells (MR = 2.35, 95% CI: 1.76 to 3.15), and in urothelial cells (MR = 3.16, 95% CI: 2.02 to 4.97). However, when the exposure method was the occupational setting or others, the MN detection using the three types of cells did not find significant differences between groups. Subgroup analysis also showed that lymphocyte MN frequencies increased significantly in both routine-culture MN assays (MR = 2.88, 95% CI: 1.15 to 7.24) and cytokinesis-block MN assays (MR = 2.89, 95% CI: 1.84 to 4.55). The performance of the MN assay with different types of cells was also compared, but no significant differences were found. Therefore, our analysis indicates that MN can be used as an effective biomarker for monitoring arsenic-exposed populations, and that MN assays conducted with lymphocytes, buccal cells, and urothelial cells do not differ in their ability to detect the genetic damage from arsenic.
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4.
Folic acid supplementation enhances arsenic methylation: results from a folic acid and creatine supplementation randomized controlled trial in Bangladesh.
Bozack, AK, Hall, MN, Liu, X, Ilievski, V, Lomax-Luu, AM, Parvez, F, Siddique, AB, Shahriar, H, Uddin, MN, Islam, T, et al
The American journal of clinical nutrition. 2019;(2):380-391
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Abstract
BACKGROUND Arsenic exposure through drinking water persists in many regions. Inorganic As (InAs) is methylated to monomethyl-arsenical species (MMAs) and dimethyl-arsenical species (DMAs), facilitating urinary excretion. Arsenic methylation is dependent on one-carbon metabolism, which is influenced by nutritional factors such as folate and creatine. OBJECTIVE This study investigated the effects of folic acid (FA) and/or creatine supplementation on the proportion of As metabolites in urine. DESIGN In a 24-wk randomized, double-blinded, placebo-controlled trial, 622 participants were assigned to receive FA (400 or 800 μg per day), 3 g creatine per day, 400 μg FA + 3 g creatine per day, or placebo. The majority of participants were folate sufficient; all received As-removal water filters. From wk 12-24, half of the participants receiving FA received placebo. RESULTS Among groups receiving FA, the mean decrease in ln(%InAs) and %MMAs and increase in %DMAs exceeded those of the placebo group at wk 6 and 12 (P < 0.05). In the creatine group, the mean decrease in %MMAs exceeded that of the placebo group at wk 6 and 12 (P < 0.05); creatine supplementation did not affect change in %InAs or %DMAs. The decrease in %MMAs at wk 6 and 12 was larger in the 800 µg FA than in the 400 µg FA group (P = 0.034). There were no differences in treatment effects between the 400 µg FA and creatine + FA groups. Data suggest a rebound in As metabolite proportions after FA cessation; at wk 24, log(%InAs) and %DMAs were not significantly different than baseline levels among participants who discontinued FA supplementation. CONCLUSIONS The results of this study confirm that FA supplementation rapidly and significantly increases methylation of InAs to DMAs. Further research is needed to understand the strong cross-sectional associations between urinary creatinine and As methylation in previous studies. This trial was registered at https://clinicaltrials.gov as NCT01050556.
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On the Use of Hair Analysis for Assessing Arsenic Intoxication.
Katz, SA
International journal of environmental research and public health. 2019;(6)
Abstract
Correlations between the concentrations of arsenic in scalp hair and in drinking water as well as in blood and/or urine have been reported. These correlations clearly show exposure⁻absorption⁻excretion relationships. In addition, arsenic metabolites such as monomethylarsonic acid and dimethylarsinic acid have been identified and quantified in these tissues and fluids, leaving little doubt that elevated levels of arsenic in the hair can reflect systemic arsenic intoxication. Consequently, hair analysis has potential merit as a screening procedure for poisoning by arsenic. However, questions regarding the exogenous versus the endogenous deposition of arsenic in the hair, and uncertainties about the normal level of arsenic in the hair remain unresolved. Pending their resolution, the determination of arsenic in hair should remain a screening tool, and clinical signs and symptoms should be employed to complete the diagnosis of arsenic poisoning.
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A urinary metabolomics study of a Polish subpopulation environmentally exposed to arsenic.
Kozłowska, L, Janasik, B, Nowicka, K, Wąsowicz, W
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2019;:44-54
Abstract
BACKGROUND Almost every organ in the human body can be affected by arsenic (As) exposure associated with various industrial processes, as well as with contaminated food, drinking water and polluted air. Much is known about high exposure to inorganic As but there is little data on the metabolic changes connected to a low exposure e.g. in people living in smelter areas. OBJECTIVES The objectives of the study were: (1) characterise urinary concentration of total arsenic (AsT) in Polish inhabitants of the vicinity of a copper smelter area, (2) speciation analysis of various forms of arsenic in girls (GL), boys (BL), women (WL) and men (ML) with a slightly elevated AsT concentration and age/sex matched groups with a substantially higher AsT concentration, (GH, BH, WH and MH - respectively), (3) comparison of metabolomics profiles of urine between the age/sex matched people with low and high AsT concentrations. METHODS Urine samples were analysed for total arsenic and its chemical forms (AsIII; AsV, methylarsonic acid, dimethylarsinic acid, arsenobetaine) using HPLC-ICP-MS. Untargeted metabolomics analysis of the urine samples was performed using UPLC system connected to Q-TOF-MS equipped with an electrospray source. The XCMS Online program was applied for feature detection, retention time correction, alignment, statistics, annotation and identification. Potentially identified compounds were fragmented and resulting spectra were compared to the spectra in the Human Metabolome Database. RESULTS Urine concentration of AsT was, as follows: GL 16.40 ± 0.83; GH 115.23 ± 50.52; BL 16.48 ± 0.83; BH 95.00 ± 50.03; WL 16.93 ± 1.21; WH 170.13 ± 96.47; ML 16.91 ± 1.20; MH 151.71 ± 84.31 μg/l and percentage of arsenobetaine in AsT was, as follows: GL 65.5 ± 13.8%, GH 87.2 ± 4.7%, BL 59.8 ± 12.5%, BH 90.5 ± 2.4%, WL 50.8 ± 14.1%, WH 90.4 ± 3.5%, ML 53.3 ± 10.0%, MH 74.6 ± 20.2%. In the people with low and high AsT concentrations there were significant differences in the intensity of signal (is.) from numerous compounds being metabolites of neurotransmitters, nicotine and hormones transformation (serotonin in the girls and women; catecholamines in the girls, boys and women; mineralocorticoids and glucocorticoids in the boys, androgens in the women and men and nicotine in the boys, women and men). These changes might have been associated with higher is. from metabolites of leucine, tryptophan, purine degradation (in the GH, WH), urea cycle (in the WH and MH), glycolysis (in the WH) and with lower is. from metabolites of tricarboxylic acid cycle (in the BH) in comparison with low AsT matched groups. In the MH vs. ML higher is. from metabolite of lipid peroxidation (4-hydroxy-2-nonenal) was observed. Additionally, the presence of significant differences was reported in is. from food components metabolites, which might have modulated the negative effects of As (vitamin C in the girls, boys and men, vitamin B6 in the girls, boys and women as well as phenolic compounds in the boys and girls). We hypothesize that the observed higher is. from metabolites of sulphate (in MH) and glucoronate degradation (in BH, WH and MH) than in the matched low AsT groups may be related to the impaired glucuronidation and sulfonation and higher is. from catecholamines, nicotine and hormones. CONCLUSION Our results indicated that even a low exposure to As is associated with metabolic changes and that urine metabolomics studies could be a good tool to reflect their wide spectrum connected to specific environmental exposure to As, e.g. in smelter areas.
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Integrative response of arsenic uptake, speciation and detoxification by Salix atrocinerea.
Navazas, A, Hendrix, S, Cuypers, A, González, A
The Science of the total environment. 2019;:422-433
Abstract
Despite arsenic (As) being very toxic with deleterious effects on metabolism, it can be tolerated and accumulated by some plants. General genetic mechanisms responsible for As tolerance in plants, including Salix species, have been described in transcriptomic analysis, but further experimental verification of the significance of particular transcripts is needed. In this study, a Salix atrocinerea clone, able to thrive in an As-contaminated brownfield, was grown hydroponically in controlled conditions under an As concentration similar to the bioavailable fraction of the contaminated area (18 mg kg-1) for 30 days. At different time points, i.e. short-term and long-term exposure, biometric data, As accumulation, phytochelatin synthesis, non-protein thiol production and expression of target genes related to these processes were studied. Results showed that S. atrocinerea presents a great tolerance to As and accumulates up to 2400 mg As kg-1 dry weight in roots and 25 mg As kg-1 dry weight in leaves. Roots reduce As V to As III rapidly, with As III being the predominant form of As accumulated in root tissues, whereas in the leaves it is As V. After 1 d of As exposure, roots and leaves show de novo synthesis and an increase in non-protein thiols as compared to the control. Integrating these data on As accumulation in the plant and its speciation, non-protein thiol production and the kinetic gene expression of related target genes, a fundamental role is highlighted for these processes in As accumulation and tolerance in S. atrocinerea. As such, this study offers new insights in the plant tolerance mechanisms to As, which provides important knowledge for future application of high-biomass willow plants in phytoremediation of As-polluted soils.
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[Migration and Transformation of Adsorbed Arsenic Mediated by Sulfate Reducing Bacteria].
Jia, QQ, Li, W, Wang, YN, Duan, JM, Liu, YC
Huan jing ke xue= Huanjing kexue. 2019;(1):430-436
Abstract
In the natural environment, arsenic (As) is mainly adsorbed on iron oxide minerals. The release of adsorbed arsenic from iron oxide minerals to the water is the main source of arsenic pollution. Microbes play a crucial role for this process. The purpose of this study was to investigate the effect of the sulfate-reducing bacteria Desulfovibrio vulgaris DP4 on the transformation and mobilization of As. The experimental results show that the released As concentration of the two systems is 0 μmol·L-1 at 0 h. Compared with the control, DP4 promotes the desorption of As(Ⅴ) before the 84 h incubation process. The released As concentration reaches the maximum value of 12.6 μmol·L-1 at 13 h, accounting for~79% of the initial total adsorbed As (16 μmol·L-1). The maximum released As concentration is~8.4 times higher than that of the control (1.5 μmol·L-1). After 84 hours, the concentration of the released As in the DP4 system is lower than the abiotic control, which suggests that the released As is readsorbed on the solid surface. During the incubation process, the As mobility is significantly correlated with Eh. The XRD results show that the crystallinity of the solid samples in the DP4 system decreases by~50%. In general, a lower crystallinity of the adsorbent indicates a higher adsorption capacity. This may be one important reason for the As readsorption after 84 h. In addition, the SEM shows that goethite is agglomerated by DP4 and the EDS results indicate that goethite is partially transformed to an Fe-S mineral. Based on XANES, arsenic-sulfur minerals were not detected in the solid phase, which further confirms the SEM-EDS results, that is, that Fe-S minerals formed in the solid phase, rather than As2S3 (AsS). The released As was readsorbed on the secondary iron mineral, resulting in a lower dissolved As concentration in the DP4 system than in the abiotic control. Furthermore, 19% As(Ⅲ) was detected in the solid phase while dissolved As(Ⅲ) was not determined during the incubation process. The results suggest that sulfate-reducing bacteria may directly reduce adsorbed As(Ⅴ) to As(Ⅲ).
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Heavy metals in food crops: Health risks, fate, mechanisms, and management.
Rai, PK, Lee, SS, Zhang, M, Tsang, YF, Kim, KH
Environment international. 2019;:365-385
Abstract
Food security is a high-priority issue for sustainable global development both quantitatively and qualitatively. In recent decades, adverse effects of unexpected contaminants on crop quality have threatened both food security and human health. Heavy metals and metalloids (e.g., Hg, As, Pb, Cd, and Cr) can disturb human metabolomics, contributing to morbidity and even mortality. Therefore, this review focuses on and describes heavy metal contamination in soil-food crop subsystems with respect to human health risks. It also explores the possible geographical pathways of heavy metals in such subsystems. In-depth discussion is further offered on physiological/molecular translocation mechanisms involved in the uptake of metallic contaminants inside food crops. Finally, management strategies are proposed to regain sustainability in soil-food subsystems.
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Isolation, Characterization, and Metal Response of Novel, Acid-Tolerant Penicillium spp. from Extremely Metal-Rich Waters at a Mining Site in Transbaikal (Siberia, Russia).
Glukhova, LB, Frank, YA, Danilova, EV, Avakyan, MR, Banks, D, Tuovinen, OH, Karnachuk, OV
Microbial ecology. 2018;(4):911-924
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Abstract
The role of fungi in metal cycling in acidic environments has been little explored to date. In this study, two acid-tolerant and metal-resistant Penicillium isolates, strains ShG4B and ShG4C, were isolated from a mine site in the Transbaikal area of Siberia (Russia). Waters at the mine site were characterized by extremely high metal concentrations: up to 18 g l-1 Fe and > 2 g l-1 each of Cu, Zn, Al, and As. Both isolates were identified as Penicillium spp. by phylogenetic analyses and they grew well in Czapek medium acidified to pH 2.5. Resistance to Cu, Cd, Ni, Co, and arsenate was in the range of 1-10 g l-1. Further experiments with Penicillium strain ShG4C demonstrated that growth in Cu-containing media was accompanied by the precipitation of Cu-oxalate (moolooite) and the formation of extracellular vesicles enriched in Cu on the mycelia. Vesicles were greatly reduced in size in Cd-containing media and were not formed in the presence of Ni or Co. Cd-oxalate was detected as a crystalline solid phase in Cd-exposed mycelia. Hydrated Ni-sulfate (retgersite) and Co-sulfate (bieberite) were detected in mycelia grown in the presence of Ni and Co, respectively. The results demonstrated that acid-tolerant and metal-resistant Penicillium constitute a component in extremophilic microbiomes, contributing to organic matter breakdown and formation of secondary solid phases at pH ranges found in acid rock drainage.