Urinary Arsenic Species and Methylation Efficiency During Pregnancy: Concentrations and Associated Factors in Spanish Pregnant Women

Background: Arsenic (As) is considered to be toxic for humans, the main routes of exposure being through drinking water and the diet. Once ingested, inorganic arsenic can be methylated sequentially to monomethyl and dimethyl arsenicals. Several factors can affect both As exposure and methylation efficiency. Objectives: To describe the urinary concentrations of the different As species and evaluate the methylation effi-ciency during pregnancy, as well as their associated factors in a birth cohort of pregnant Spanish women. Methods: Participants in this cross-sectional study were 1017 pregnant women from two areas of Spain who had taken part in the INMA (Environment and Childhood) project (2003 & ndash;2008). Total As (organic and inorganic compounds) and its main metabolites (monomethylarsonic acid, [MMA], dimethylarsinic acid, [DMA], inorganic As [iAs]) and arsenobetaine [AB]) were measured in urine samples collected during the first trimester. Socio-demographic and dietary information was collected through questionnaires. Multivariate linear regression models were used to explore the association between As species concentrations and covariates. Arsenic methylation efficiency was determined through the percentages of the metabolites and using As methylation phenotypes, obtained from principal component analysis. Results: Median urine concentrations were 33.0, 21.6, 6.5, 0.35 and 0.33 lig/g creatinine for total As, AB, DMA, MMA and iAs, respectively. Daily consumption of rice and seafood during the first trimester of pregnancy were positively associated with the concentration of As species (i.e., beta [CI95%] = 0.36 [0.09, 0.64] for rice and iAs, and 1.06 [0.68, 1.44] for seafood and AB). TAs, AB and iAs concentrations, and DMA and MMA concentrations were associated with legume and vegetable consumption, respectively. The medians of the percentage of As metabolites were 89.7 for %DMA, 5.1 for %MMA and 4.7 for %iAs. Non-smoker women and those with higher body mass index presented a higher methylation efficiency (denoted by a higher %DMA and lower %MMA). Discussion: Certain dietary, lifestyle, and environmental factors were observed to have an influence on both As species concentrations and methylation efficiency in our population. Further birth cohort studies in low exposure areas are necessary to improve knowledge about arsenic exposure, especially to inorganic forms, and its potential health impact during childhood.This study was supported by grants from Instituto de Salud Carlos III, Spain [FIS-FEDER: 07/0314; FIS 11/01007, 13/1944, 16/1288, 19/1338; Miguel Servet-FEDER: CP15/0025, CPII20/00006; FIS-FSE: 17/00260; Miguel Servet-FSE: MS15/0025, MS20/0006; PI06/0867 and FIS-PI18/01142 incl. FEDER funds] , Generalitat Valenciana, Spain BEST/2020/059, Department of Health of the Basque Government, Spain (2005111093) , Provincial Government of Gipuzkoa (DFG06/002) , and annual agreements with the municipalities in the study area (Zumarraga, Urretxu, Legazpi, Azkoitia, Azpeitia and Beasain)

Reaction Mechanism and Substrate Specificity of Iso-orotate Decarboxylase: A Combined Theoretical and Experimental Study

The C-C bond cleavage catalyzed by metal-dependent iso-orotate decarboxylase (IDCase) from the thymidine salvage pathway is of interest for the elucidation of a (hypothetical) DNA demethylation pathway. IDCase appears also as a promising candidate for the synthetic regioselective carboxylation of N-heteroaromatics. Herein, we report a joint experimental-theoretical study to gain insights into the metal identity, reaction mechanism, and substrate specificity of IDCase. In contrast to previous assumptions, the enzyme is demonstrated by ICPMS/MS measurements to contain a catalytically relevant Mn2+ rather than Zn2+. Quantum chemical calculations revealed that decarboxylation of the natural substrate (5-carboxyuracil) proceeds via a (reverse) electrophilic aromatic substitution with formation of CO2. The occurrence of previously proposed tetrahedral carboxylate intermediates with concomitant formation of HCO3- could be ruled out on the basis of prohibitively high energy barriers. In contrast to related o-benzoic acid decarboxylases, such as γ-resorcylate decarboxylase and 5-carboxyvanillate decarboxylase, which exhibit a relaxed substrate tolerance for phenolic acids, IDCase shows high substrate fidelity. Structural and energy comparisons suggest that this is caused by a unique hydrogen bonding of the heterocyclic natural substrate (5-carboxyuracil) to the surrounding residues. Analysis of calculated energies also shows that the reverse carboxylation of uracil is impeded by a strongly disfavored uphill reaction

Influence of genetic polymorphisms on arsenic methylation efficiency during pregnancy: Evidence from a Spanish birth cohort

Background: Inorganic arsenic (iAs) is a widespread toxic metalloid. It is well-known that iAs metabolism and its toxicity are mediated by polymorphisms in AS3MT and other genes. However, studies during pregnancy are scarce. We aimed to examine the role of genetic polymorphisms in AS3MT, GSTO2, N6AMT1, MTHFR, MTR, FTCD, CBS, and FOLH1 in iAs methylation efficiency during pregnancy. Methods: The study included 541 pregnant participants from the INMA (Environment and Childhood) Spanish cohort. Using high-performance liquid chromatography coupled to inductively coupled plasma-tandem mass, we measured arsenic (iAs and the metabolites monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)) in urine samples collected during the first trimester. iAs methylation efficiency was determined based on relative concentrations of the As metabolites in urine (%MMA, %DMA, and %iAs). Thirty-two single nucleotide polymorphisms (SNPs) in nine genes were determined in maternal DNA; AS3MT haplotypes were inferred. We assessed the association between genotypes/haplotypes and maternal As methylation efficiency using multivariate linear regression models. Results: The median %MMA and %DMA were 5.3 %, and 89 %, respectively. Ancestral alleles of AS3MT SNPs (rs3740393, rs3740390, rs11191453, and rs11191454) were significantly associated with higher %MMA, %iAs, and lower %DMA. Pregnant participants with zero copies of the GGCTTCAC AS3MT haplotype presented a higher %MMA. Statistically significant associations were also found for the FOLH1 SNP rs202676 (β 0.89 95%CI: 0.24, 1.55 for carriers of the G allele vs. the A allele). Conclusions: Our study shows that ancestral alleles in AS3MT polymorphisms were associated with lower As methylation efficiency in early pregnancy and suggests that FOLH1 also plays a role in As methylation efficiency. These results support the hypothesis that As metabolism is multigenic, being a key element for identifying susceptible populations

Prenatal Metals Exposure and pre-adolescents’ Emotional and Behavioral Problems

Emotional and behavioral problems during childhood raise the risk of subsequent developmental of mental disorders. Our aim was to study the association between maternal metal and trace element concentrations during gestation and these problems in 9 year-old children. The study sample comprised Spanish mother-child pairs in the INMA project (n = 1003). Metals and trace elements (As, Cd, Co, Cu, Mo, Ni, Pb, Sb, Se, Tl and Zn) were measured in urine samples collected during pregnancy. Inorganic As metabolites were speciated in a subsample (n = 729). Emotional and behavioral problems were assessed using the Child Behavior Checklist (CBCL) composed of three scales: internalizing, externalizing and total problems. Sociodemographic, dietary and exposure to other environmental pollutants were obtained through questionnaires. Single nucleotide polymorphisms in brain- and metabolism-related genes APOE, BDNF, GSTP1, and PON1 were determined in cord blood. Multivariate negative binomial models were used. The interaction with sex and genotypes was evaluated including interaction terms. A multi-element analysis was carried out by a principal component analysis. Higher concentrations of Cu, monomethylarsonic acid, and Pb during pregnancy were associated with an increased incidence ratio risk (IRR) between 4.6 and 7.5% for internalizing and externalizing problems for all three CBCL scales in the children. Increasing Mo, Ni and Co concentrations were associated with higher IRR for internalizing problems (up to 8%), and Cd for externalizing problems (6.7%). Modifications by sex and genotypes were found for several associations. Multi-element analysis associated multiple metals and trace elements (Ni, Cu, Se, Cd and Pb) with higher internalizing problems.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. We are grateful to all the participants and their families for taking part in this study. We also appreciate the generous contribution in the study of all INMA members. A full roster of the INMA Project researchers can be found at http://www.proyectoinma.org/presentacion-inma/listado-investigadores/en_listado-investigadores.html. This study was supported by grants from Spanish government through the Ministry of Universities under the grant CAS21/00008 and grant for the requalification of the Spanish University, financed by the European Union, NextGeneration EU, Instituto de Salud Carlos III [FIS-FEDER: 13/1944, 16/1288, 17/00663 and 19/1338; FIS-FSE: 17/00260; Miguel Servet-FSE: MSII20/0006, FIS-PI06/0867, FIS-PI09/00090, CPII18/00018], CIBERESP, Department of Health of the Basque Government (2005111093, 2009111069, 2013111089, 2015111065), Generalitat Valenciana [BEST/2020/059, AICO/2020/285 and CIAICO/2021/132] and the Provincial Government of Gipuzkoa (DFG06/002, DFG08/001 and DFG15/221 and DFG 89/17). We also acknowledge support from the Spanish Ministry of Science and Innovation and the State Research Agency through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program.Peer reviewe

Arsenic in mushrooms : hyperaccumulation and speciation

Pilze sind wichtige Bestandteile unserer Umwelt und in vielerlei Hinsicht einzigartig. So können sie zum Beispiel extreme Konzentrationen von (Spuren-)Elementen anreichern. Im Fall von Arsen wurden bereits bis zu 7000 mg/kg Trockenmasse (dm) im Kronenbecherling (Sarcosphaera coronaria) gefunden. Kaum ein anderer Organismus enthält solch hohe Arsenkonzentrationen. Die Fähigkeit Arsen anzureichern hängt von der Pilzspezies ab, aber auch die Erde gilt als Einflussfaktor. In dieser Dissertation wurde eine neue hyperakkumulierende Pilzspezies entdeckt, mit bis zu 1300 mg As/kg dm, der schwarzblauende Röhrling Cyanoboletus pulverulentus. Da das Arsen als vermutlich krebserregende Dimethylarsinsäure vorlag, sollte ein regelmäßiger Verzehr dieses Pilzes vermieden werden.Die Arsenspeziation von Pilzen besteht nicht immer nur aus einer Verbindung, was anhand der Gattungen Elaphomyces (Hirschtrüffel) und Ramaria (Korallenpilze) gezeigt wurde. Hirschtrüffel enthielten Methylarsonsäure als Hauptspezies, aber auch hohe Konzentrationen an Trimethylarsinoxid. Beide Spezies kommen in den meisten anderen Pilzen höchstens in Spuren vor. Erstaunlicherweise wurden auch signifikante Konzentrationen der sehr selten vorkommenden dreiwertigen methylarsonigen Säure gefunden.Die dominierende Arsenverbindung in Ramaria Proben war Arsenobetain. Diese Spezies wird zwar normalerweise der marinen Umwelt zugeschrieben, ist aber auch häufig die Hauptspezies in Pilzen. Außergewöhnlicher war daher die Entdeckung von Dimethylarsinoylacetat und Trimethylarsinopropionat. Diese Spezies sind zwar hin und wieder in marinen Organismen präsent, wurden bis jetzt allerdings nicht in terrestrischen Proben detektiert. Außerdem wurde eine neue natürliche Arsenverbindung identifiziert, das (3-hydroxypropyl) trimethylarsonium Ion, welche Homoarsenocholin genannt wurde. Diese könnte einen wichtigen Baustein für die Aufklärung der Biotransformierungsmechanismen von Arsen darstellen.Fungi are important organisms in our environment and unique in many ways. For example, some macrofungi are able to accumulate remarkable concentrations of (trace) elements in their fruit-bodies. One of these elements is arsenic, where up to 7000 mg/kg dry mass (dm) have been found in the crown cup (Sarcosphaera coronaria). Such concentrations are hardly ever reported for any natural living organism. Amongst macrofungi, the ability to accumulate arsenic is species specific, but the soil is also regarded as influencing factor. Within this thesis, a new hyperaccumulating mushroom was identified, with up to 1300 mg As/kg dm: The edible ink stain bolete Cyanoboletus pulverulentus. Because the arsenic was present as the probably carcinogenic dimethylarsinic acid, frequent consumption of this mushroom should be avoided.Mushrooms not always contain just one arsenic species, which was demonstrated with samples of the genera Elaphomyces (deer truffles) and Ramaria (coral mushrooms). Elaphomyces samples contained methylarsonic acid as main arsenical, but also high concentrations of trimethylarsine oxide. Both compounds are only detected in trace concentrations or even not at all in most other macrofungi. Strikingly, there were also significant concentrations of the otherwise rarely detected methylarsonous acid.The major arsenic compound in samples of the genus Ramaria was arsenobetaine. Although otherwise only found in the marine environment, this compound is often reported as the main arsenical in mushrooms. More remarkable was therefore the detection of dimethylarsinoylacetate and trimethylarsoniopropionate. These compounds are sometimes found in the marine biota, but have never been described for terrestrial samples before. Finally, the arsenic species (3-hydroxypropyl) trimethylarsonium ion that we named homoarsenocholine was identified for the first time ever in nature and could be an important compound for the elucidation of the biotransformation pathways of arsenic.vorgelegt von Simone Braeuer, MScZusammenfassungen in Deutsch und EnglischKarl-Franzens-Universität Graz, Dissertation, 2018OeBB(VLID)267963

Occurrence of major and trace elements in powdered milk from Argentina

The concentrations of major and trace elements in Argentinean commercial powdered milk samples were determined with inductively coupled plasma mass spectrometry. Also the daily intake (DI) was calculated for adults and infants. The concentrations of B, Mg, Na, K and Ca were significantly higher in skimmed milk. Cu, Mo, Fe, Mn and Zn were significantly higher in infant formula. All the DIs were below the tolerable upper intake levels. The mean As concentration (26.0 ± 8.6 ng/g) in the powdered skimmed milk samples was slightly higher than in the others. Mean Pb concentrations ranged from 4.1 ± 2.1 to 13.5 ± 8.2 ng/g. The highest mean U concentration was 7.8 ± 2.6 ng/g for whole milk. This study contributes to the knowledge of major and trace elements in powdered milk and its contribution to the diet in Argentina.Fil: Arellano, Flavia Elisa. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; ArgentinaFil: Braeuer, Simone. University of Graz; AustriaFil: Fernandez Cirelli, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Goessler, Walter. University of Graz; AustriaFil: Pérez Carrera, Alejo Leopoldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentin

Simultaneous selenium and sulfur speciation analysis in cultivated Pleurotus pulmonarius mushroom

Selenium (Se) and sulfur (S) speciation analysis in edible and medicinal Se enriched P. pulmonarius extracts was performed. Mycelium, colonized substrate, and fruiting bodies at different harvesting times were analyzed using ion-pairing reversed-phase chromatography coupled to an ICPMS/MS detector. Extraction efficiencies in en-zymatically digested and aqueous extracts were between 45.3 and 109% for Se, depending on the sample type. Selenomethionine (Se-Met) was found to be the major Se-compound, together with a number of unknown Se-species. Cystine (Cys(2)), methionine (Met), and sulfate were also detected and quantified in all samples. Most of the Se-Met (84.0%) and met (75.8%) were found to be in free form in the fruiting body, in contrast with the mycelium where 53.4% of Se-Met and 80.5% of met is incorporated into proteins

Artificial cellulose standards as calibration standards for wavelength-dispersive X-ray fluorescence analysis of elements in plant samples

This research explores the possibilities and limitations of WD-XRF, applied as a method for quantification of 20 elements in plant material, using spiked cellulose standards for calibration. Three different analytical methods were investigated: 1) standards created from pure spiked cellulose; 2) spiked cellulose mixed with 20% of binder and 3) spiked cellulose applied as a thin layer on an inert carrier. Sensitivity, linearity, limit of detection, limit of quantification, repeatability, intralaboratory reproducibility, and accuracy were determined and compared. The accuracy of the investigated methods was tested by analysis of standard reference materials and comparison with other routinely used analytical techniques (ICP-OES and ICP-MS). The comparison included real plant samples which were collected from the environment characterized by different pollution levels. The accuracy of the semiquantitative standardless method was also considered and compared with other investigated methods. Tested methods can be very precise, with good intralaboratory reproducibility over wide linear range.Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4615