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1.
Environ Sci Technol ; 58(29): 12755-12762, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38984753

RESUMO

Due to the increasing number of chemicals released into the environment, nontarget screening (NTS) analysis is a necessary tool for providing comprehensive chemical analysis of environmental pollutants. However, NTS workflows encounter challenges in detecting both known and unknown pollutants with common chromatography high-resolution mass spectrometry (HRMS) methods. Identification of unknowns is hindered by limited elemental composition information, and quantification without identical reference standards is prone to errors. To address these issues, we propose the use of inductively coupled plasma mass spectrometry (ICP-MS) as an element-specific detector. ICP-MS can enhance the confidence of compound identification and improve quantification in NTS due to its element-specific response and unambiguous chemical composition information. Additionally, mass balance calculations for individual elements (F, Br, Cl, etc.) enable assessment of total recovery of those elements and evaluation of NTS workflows. Despite its benefits, implementing ICP-MS in NTS analysis and environmental regulation requires overcoming certain shortcomings and challenges, which are discussed herein.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais , Espectrometria de Massas , Monitoramento Ambiental/métodos , Espectrometria de Massas/métodos , Poluentes Ambientais/análise
2.
Anal Bioanal Chem ; 416(11): 2677-2682, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-37994920

RESUMO

Rice is a staple food and known to accumulate inorganic arsenic (iAs), which is a class 1 carcinogen to humans. Arsenic field-deployable method kits, designed for water testing, are able to screen iAs in rice, to assure food safety and quick decision-making without the need for laboratory analysis. For the arsenic extraction within the field method, nitric acid is used. To make the field method on-site safer, cost-effective and easier to handle, the method was adapted using a Cola in the extraction process. The adapted field-deployable method was tested by screening a total of 30 rice and rice products from the Austrian market. To verify the results obtained by the Cola extraction field-deployable method, the obtained iAs concentration was compared to HPLC-ICP-MS results. The Cola extraction field method obtained an LOD of 39 µg iAs kg-1 rice, and with an average reproducibility of 14% RSD, the method was capable of recording no false-negative but 7% false-positive values at the 2023 updated European Commission (EC) limits for rice. All, but one, screened rice samples were within the EU limits for iAs in rice and rice products.


Assuntos
Arsênio , Arsenicais , Oryza , Humanos , Arsênio/análise , Reprodutibilidade dos Testes , Contaminação de Alimentos/análise , Arsenicais/análise
3.
Anal Bioanal Chem ; 416(11): 2809-2818, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38189919

RESUMO

In this study, arsenic (As) speciation was investigated in the freshwater alga Chlamydomonas reinhardtii treated with 20 µg/L arsenate using fractionation as well as ICP-MS/ESI-MS analyses and was compared with the known As metabolite profile of wild-grown Saccharina latissima. While the total As accumulation in C. reinhardtii was about 85% lower than in S. latissima, the relative percentage of arsenolipids was significantly higher in C. reinhardtii (57.0% vs. 5.01%). As-containing hydrocarbons and phospholipids dominated the hydrophobic As profile in S. latissima, but no As-containing hydrocarbons were detectable in C. reinhardtii. Instead for the first time, an arsenoriboside-containing phytol (AsSugPhytol) was found to dominate the hydrophobic arsenicals of C. reinhardtii. Interestingly, this compound and its relatives had so far been only found in green marine microalgae, open sea plankton (mixed assemblage), and sediments but not in brown or red macroalgae. This compound family might therefore relate to differences in the arsenic metabolism between the algae phyla.


Assuntos
Arsênio , Arsenicais , Chlamydomonas reinhardtii , Algas Comestíveis , Laminaria , Arsenicais/química , Arsênio/metabolismo , Chlamydomonas reinhardtii/metabolismo , Hidrocarbonetos
4.
J Sci Food Agric ; 104(11): 6957-6965, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-38597303

RESUMO

BACKGROUND: Including seaweed in cattle feed has gained increased interest, but it is important to take into account that the concentration of toxic metals, especially arsenic, is high in seaweed. This study investigated the arsenic species in milk from seaweed-fed cows. RESULTS: Total arsenic in milk of control diets (9.3 ± 1.0 µg As kg-1, n = 4, dry mass) was significantly higher than seaweed-based diet (high-seaweed diet: 7.8 ± 0.4 µg As kg-1, P < 0.05, n = 4, dry mass; low-seaweed diet: 6.2 ± 1.0 µg As kg-1, P < 0.01, n = 4, dry mass). Arsenic speciation showed that the main species present were arsenobetaine (AB) and arsenate (As(V)) (37% and 24% of the total arsenic, respectively). Trace amounts of dimethylarsinic acid (DMA) and arsenocholine (AC) have also been detected in milk. Apart from arsenate being significantly lower (P < 0.001) in milk from seaweed-fed cows than in milk from the control group, other arsenic species showed no significant differences between groups. CONCLUSION: The lower total arsenic and arsenate in seaweed diet groups indicates a possible competition of uptake between arsenate and phosphate, and the presence of AC indicates that a reduction of AB occurred in the digestive tract. Feeding a seaweed blend (91% Ascophyllum nodosum and 9% Laminaria digitata) does not raise As-related safety concerns for milk. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Ração Animal , Arsênio , Leite , Alga Marinha , Animais , Alga Marinha/química , Alga Marinha/metabolismo , Bovinos/metabolismo , Leite/química , Leite/metabolismo , Arsênio/análise , Arsênio/metabolismo , Ração Animal/análise , Feminino , Dieta/veterinária , Arsenicais/análise , Arsenicais/metabolismo , Arsenicais/química , Arseniatos/análise , Arseniatos/metabolismo , Arseniatos/química , Contaminação de Alimentos/análise
5.
Anal Bioanal Chem ; 415(6): 1195-1204, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36633619

RESUMO

Per- and polyfluoroalkyl substances (PFAS) are emerging organic pollutants and can occur in surface and groundwater. To identify the degree of pollution in surface water with PFAS, often targeted HPLC-ESI-MS/MS has been employed in which commonly 30-40 compounds are analyzed. However, other PFAS and organofluorines remain undetected. We sampled surface water of the river Spree and the Teltow Canal in Berlin, Germany, which are affected by the effluent discharge of wastewater treatment plants. Here, we employed high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) for measuring extractable organofluorines (EOF) and compared in a mass balance approach the total fluorine to the identified and quantified PFAS from the targeted analysis. The analysis highlights that the EOF are in the range expected for an urban river system (Winchell et al. in Sci Total Environ 774, 2021). However, downstream of an effluent discharge, the EOF increased by one order of magnitude, e.g., 40.3 to 574 ng F L-1, along the Teltow Canal. From our target analytes, mostly short-chained perfluorinated carboxylic acids and sulfonates occur in the water, which however makes up less than 10% of the EOF. The increase in EOF in the Teltow Canal correlates well with the increase of perfluorohexanoic acid (PFHxA), indicating that PFHxA is characteristic for the discharged EOF but not responsible for the increase. Hence, it points to PFHxA precursor discharge. The study highlights that EOF screening using HR-CS-GFMAS is necessary to identify the full scale of pollution with regard to PFAS and other organofluorines such as pharmaceutical compounds from the effluent of WWTPs.

6.
Anal Chem ; 93(37): 12733-12739, 2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34499489

RESUMO

Nanoscale secondary ion mass spectrometry (NanoSIMS) is a dynamic SIMS technique, which offers high spatial resolution allowing the mapping of chemical elements at the nanometer scale combined with high sensitivity. However, SIMS for mercury analysis is a challenging issue due to the low secondary ion yield and has never been done on NanoSIMS. The introduction of an rf plasma oxygen primary ion source on NanoSIMS enabled higher lateral resolution and higher sensitivity for electropositive elements such as most metals. In this paper, for the first time, mercury analysis by NanoSIMS was developed applying the new rf plasma O- ion source. All mercury isotopes could be detected as Hg+ secondary ions and the isotopic pattern corresponded to their natural isotopic abundances. Furthermore, Hg+ detection in HgSe nanocrystals has been investigated where polyatomic interferences from selenium clusters were identified and separated by high mass resolution (ΔM/M ≥ 3200). However, in the presence of selenium a strong matrix effect was observed, decreasing the Hg+ secondary ion yield. In addition, a detection of Se+ ions was possible, too. The newly developed method was successfully applied to nanoscale localization by chemical imaging of HgSe particles accumulated in the liver tissue of sperm whale (Physeter macrocephalus). This demonstrated the applicability of NanoSIMS not only for mercury detection in surface analysis but also for mercury mapping in biological samples.


Assuntos
Mercúrio , Selênio , Animais , Fígado , Espectrometria de Massa de Íon Secundário , Baleias
7.
Analyst ; 146(21): 6665-6667, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34558571

RESUMO

Correction for 'Spatiotemporal distribution and speciation of silver nanoparticles in the healing wound' by Marco Roman et al., Analyst, 2020, 145, 6456-6469, DOI: 10.1039/D0AN00607F.

8.
Environ Microbiol ; 22(6): 2346-2364, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32250010

RESUMO

Microbial reduction of soluble selenium (Se) or tellurium (Te) species results in immobilization as elemental forms and this process has been employed in soil bioremediation. However, little is known of direct and indirect fungal interactions with Se-/Te-bearing ores. In this research, the ability of Phoma glomerata to effect transformation of selenite and tellurite was investigated including interaction with Se and Te present in sulfide ores from the Kisgruva Proterozoic volcanogenic deposit. Phoma glomerata could precipitate elemental Se and Te as nanoparticles, intracellularly and extracellularly, when grown with selenite or tellurite. The nanoparticles possessed various surface capping molecules, with formation being influenced by extracellular polymeric substances. The presence of sulfide ore also affected the production of exopolysaccharide and protein. Although differences were undetectable in gross Se and Te ore levels before and after fungal interaction using X-ray fluorescence, laser ablation inductively coupled plasma mass spectrometry of polished flat ore surfaces revealed that P. glomerata could effect changes in Se/Te distribution and concentration indicating Se/Te enrichment in the biomass. These findings provide further understanding of fungal roles in metalloid transformations and are relevant to the geomicrobiology of environmental metalloid cycling as well as informing applied approaches for Se and Te immobilization, biorecovery or bioremediation.


Assuntos
Phoma/metabolismo , Selênio/metabolismo , Telúrio/metabolismo , Biodegradação Ambiental , Biotransformação , Nanopartículas , Sulfetos , Erupções Vulcânicas
9.
Analyst ; 145(20): 6456-6469, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-32893269

RESUMO

The medical application of nanomaterials is growing fast. Amongst the most widely used, silver nanoparticles are antimicrobial agents whose key application is the care of burns and chronic wounds. Still, their absorption, distribution, metabolism and excretion behaviour in vivo has not yet been systematically investigated. We collected full-profile specimens of skin from four hospital patients with mid-to-deep thickness burns or equivalent skin wounds, treated with dressings containing silver nanoparticles or silver sulfadiazine. Synchrotron radiation µXRF/µXANES and laser ablation-ICP-MS were used to provide the first semi-quantitative/high resolution direct information on the spatiotemporal distribution and speciation of silver in vivo. The metal was rapidly released onto the wound surface, followed by a significant structure-dependent penetration into the damaged tissues. This was accompanied by sequential processes of metallic silver dissolution, chloride complexation, change to metal-thiol protein complexes, and final mobilization into deeper skin layers towards the vascular networks. Complete local clearance of silver was observed after 12 days of treatment in the case of full healing. The results provide a complete insight into the dynamics of silver in real human wounds, and a new basis for the design of innovative silver nanomaterials with optimal antibacterial efficacy and minimized risk for the patient.


Assuntos
Queimaduras , Nanopartículas Metálicas , Bandagens , Humanos , Prata , Sulfadiazina de Prata
10.
Anal Chem ; 91(1): 1164-1170, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30516958

RESUMO

The coupling of flow field flow fractionation (FlFFF) with ICP-MS/MS for the fractionation and analysis of natural nanoparticles (NPs) in environmental samples is becoming more popular. However, the applicability of this technique to nonaqueous samples, such as gas condensates from petroleum hydrocarbon samples, has not been reported yet. In this study, an asymmetric flow-field flow fractionation (AF4) system coupled with UV and MALS detectors has been optimized to perform the fractionation of natural NPs present in a gas condensate sample, using THF as the carrier liquid. Prior to this, STEM images indicated the presence of both large (200 nm and more) and smaller (50 nm and less) particles, whose irregular shape is probably due to agglomeration. AF4-UV-MALS-ICP-MS/MS confirmed the presence of various NPs and colloids, some containing aromatic compounds as well as various metals, including Hg. The recovery against an injection without crossflow is around 75% for most metals. The presence of Hg-containing NPs was confirmed with offline single particle ICP-MS (spICP-MS), using THF as a solvent. These NPs were identified as HgS using STEM-EDX. These results highlight, for the first time, that particulate matter may contaminate gas condensates with a series of elements (Al, P, S, Ti, V, Mn, Fe, Co, Cu, Zn, As, Se, Cd, Hg, and Pb), which can make the upstream use problematic, especially for mercury.

11.
Anal Bioanal Chem ; 411(3): 565-580, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30511253

RESUMO

This paper presents a combination of elemental and isotopic spatial distribution imaging with near-infrared hyperspectral imaging (NIR-HSI) to evaluate the diagenetic status of skeletal remains. The aim is to assess how areas with biogenic n(87Sr)/n(86Sr) isotope-amount ratios may be identified in bone material, an important recorder complementary to teeth. Elemental (C, P, Ca, Sr) and isotopic (n(87Sr)/n(86Sr)) imaging were accomplished via laser ablation (LA) coupled in a split stream to a quadrupole inductively coupled plasma mass spectrometer (ICP-QMS) and a multicollector inductively coupled plasma mass spectrometer (MC ICP-MS) (abbreviation for the combined method LASS ICP-QMS/MC ICP-MS). Biogenic areas on the bone cross section, which remained unaltered by diagenetic processes, were localized using chemical indicators (I(C)/I(Ca) and I(C) × 10/I(P) intensity ratios) and NIR-HSI at a wavelength of 1410 nm to identify preserved collagen. The n(87Sr)/n(86Sr) isotope signature analyzed in these areas was in agreement with the biogenic bulk signal revealed by solubility profiling used as an independent method for validation. Elevated C intensities in the outer rim of the bone, caused by either precipitated secondary minerals or adsorbed humic materials, could be identified as indication for diagenetic alteration. These areas also show a different n(87Sr)/n(86Sr) isotopic composition. Therefore, the combination of NIR-HSI and LASS ICP-QMS/MC ICP-MS allows for the determination of preserved biogenic n(87Sr)/n(86Sr) isotope-amount ratios, if the original biogenic material has not been entirely replaced by diagenetic material. Graphical abstract ᅟ.


Assuntos
Osso e Ossos/química , Lasers , Espectrometria de Massas/métodos , Imagem Molecular/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Isótopos de Estrôncio/química , Animais , Humanos , Substâncias Húmicas/análise , Reprodutibilidade dos Testes
12.
Anal Bioanal Chem ; 411(19): 4973-4985, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31152227

RESUMO

Brown macroalgae Saccharina latissima (30-40 individuals) and Alaria esculenta (15-20 individuals) were collected from natural populations in winter in Iceland. The algal thalli were sectioned into different parts (e.g. holdfast, stipe, old frond, young frond and sori-containing frond sections) that differed in age and biological function. The work elucidated that arsenic (As) was not uniformly distributed within the two brown macroalgal species, with lower levels of total As were found in the stipe/midrib compared to other thallus parts. The arsenosugars mirrored the total arsenic in the seaweed mainly due to AsSugSO3 being the most abundant As species. However, arsenic speciation using parallel HPLC-ICP-MS/ESI-MS elucidated that the arsenic-containing lipids (AsL) had a different distribution where the arsenosugarphospholipids (AsPL) differed by approximately a factor of 4 between the sections containing the lowest and highest concentrations of AsPLs. When placing the sections in order of metabolic activity and an estimate of tissue age, there appeared to be a relationship between the activity and AsPLs, with lower levels of AsPLs in oldest parts. This is the first time such a relationship has been shown for AsLs. Hence, by applying sophisticated analytical techniques, it was possible to gain a deeper understanding of arsenolipids in seaweed.


Assuntos
Arsênio/metabolismo , Metabolismo dos Lipídeos , Phaeophyceae/metabolismo , Alga Marinha/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Phaeophyceae/classificação , Plantas Comestíveis/metabolismo , Controle de Qualidade , Especificidade da Espécie , Espectrometria de Massas por Ionização por Electrospray/métodos
13.
Adv Exp Med Biol ; 1055: 67-100, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29884962

RESUMO

This chapter is focussing on the interaction of arsenic, mercury and selenium with plans. Aspects of biotransformations are discussed, before the analytical methodologies are listed and critically appraised in the second part. A holistic view is given, starting from the soil environment and continuing to the plant roots and the translocations into the upper part of the plants. Under different soil conditions, different kinds of elemental species are identified, which have an impact on how the elemental species are taken up by the plant. The uptake mechanisms of these elemental species are explained and compared before the biotransformation reactions of all elemental species in the plant root; their transport into the vacuoles and translocation to the leaves and grains are discussed. Here in particular the interaction with sulphur-rich phytochelatins is described for all three elemental species. Since the sulphur chemistry is so important for the uptake, bioaccumulation and translocation of the metals and metalloids, a subchapter about sulphur chemistry in plants has been added. All aspects of biotransformation dealt with in this chapter is finally rounded up by a thorough description of the analytical methodology given with a focus on the use of HPLC-ICPMS/ESI-MS for both quantitative and molecular analysis.


Assuntos
Arsênio/metabolismo , Mercúrio/metabolismo , Plantas/metabolismo , Selênio/metabolismo , Enxofre/metabolismo , Biotransformação
14.
Anal Chem ; 88(24): 12419-12426, 2016 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-28193074

RESUMO

Maternal diet and lifestyle choices may affect placental transfer of cobalamin (Cbl) to the fetus. Fetal liver concentration of Cbl reflects nutritional status with regards to vitamin B12, but at these low concentration current Cbl measurement methods lack robustness. An analytical method based on enzymatic extraction with subsequent reversed-phase-high-pressure liquid chromatography (RP-HPLC) separation and parallel ICPMS and electrospray ionization (ESI)-Orbitrap-MS to determine specifically Cbl species in liver samples of only 10-50 mg was developed using 14 pig livers. Subsequently 55 human fetal livers were analyzed. HPLC-ICPMS analysis for cobalt (Co) and Cbl gave detection limits of 0.18 ng/g and 0.88 ng/g d.m. in liver samples, respectively, with a recovery of >95%. Total Co (Cot) concentration did not reflect the amount of Cbl or vitamin B12 in the liver. Cbl bound Co contributes only 45 ± 15% to Cot. XRF mapping and µXANES analysis confirmed the occurrence of non-Cbl cobalt in pig liver hot spots indicating particular Co. No correlations of total cobalt nor Cbl with fetal weight or weeks of gestation were found for the human fetal livers. Although no gender difference could be identified for total Co concentration, female livers were significantly higher in Cbl concentration (24.1 ± 7.8 ng/g) than those from male fetuses (19.8 ± 7.1 ng/g) (p = 0.04). This HPLC-ICPMS method was able to quantify total Cot and Cbl in fetus liver, and it was sensitive and precise enough to identify this gender difference.


Assuntos
Cobalto/análise , Fígado/química , Fígado/embriologia , Vitamina B 12/análise , Animais , Cromatografia Líquida de Alta Pressão/métodos , Feminino , Humanos , Masculino , Espectrometria de Massas por Ionização por Electrospray/métodos , Suínos
15.
Anal Chem ; 87(22): 11271-6, 2015 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-26506262

RESUMO

Rice is a staple food eaten by more than 50% of the world's population and is a daily dietary constituent in most South East Asian countries where 70% of the rice export comes from and where there is a high level of arsenic contamination in groundwater used for irrigation. Research shows that rice can take up and store inorganic arsenic during cultivation, and rice is considered to be one of the major routes of exposure to inorganic arsenic, a class I carcinogen for humans. Here, we report the use of a screening method based on the Gutzeit methodology to detect inorganic arsenic (iAs) in rice within 1 h. After optimization, 30 rice commodities from the United Kingdom market were tested with the field method and were compared to the reference method (high-performance liquid chromatography-inductively coupled plasma-mass spectrometry, HPLC-ICP-MS). In all but three rice samples, iAs compound can be determined. The results show no bias for iAs using the field method. Results obtained show quantification limits of about 50 µg kg(-1), a good reproducibility for a field method of ±12%, and only a few false positives and negatives (<10%) could only be recorded at the 2015 European Commission (EC) guideline for baby rice of 100 µg kg(-1), while none were recorded at the maximum level suggested by the World Health Organization (WHO) and implemented by the EC for polished and white rice of 200 µg kg(-1). The method is reliable, fast, and inexpensive; hence, it is suggested to be used as a screening method in the field for preselection of rice which violates legislative guidelines.


Assuntos
Arsênio/análise , Técnicas de Química Analítica/métodos , Contaminação de Alimentos/análise , Oryza/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas
16.
BMC Med ; 13: 18, 2015 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-25630355

RESUMO

BACKGROUND: Maternal smoking is one of the most important modifiable risk factors for low birthweight, which is strongly associated with increased cardiometabolic disease risk in adulthood. Maternal smoking reduces the levels of the methyl donor vitamin B12 and is associated with altered DNA methylation at birth. Altered DNA methylation may be an important mechanism underlying increased disease susceptibility; however, the extent to which this can be induced in the developing fetus is unknown. METHODS: In this retrospective study, we measured concentrations of cobalt, vitamin B12, and mRNA transcripts encoding key enzymes in the 1-carbon cycle in 55 fetal human livers obtained from 11 to 21 weeks of gestation elective terminations and matched for gestation and maternal smoking. DNA methylation was measured at critical regions known to be susceptible to the in utero environment. Homocysteine concentrations were analyzed in plasma from 60 fetuses. RESULTS: In addition to identifying baseline sex differences, we found that maternal smoking was associated with sex-specific alterations of fetal liver vitamin B12, plasma homocysteine and expression of enzymes in the 1-carbon cycle in fetal liver. In the majority of the measured parameters which showed a sex difference, maternal smoking reduced the magnitude of that difference. Maternal smoking also altered DNA methylation at the imprinted gene IGF2 and the glucocorticoid receptor (GR/NR3C1). CONCLUSIONS: Our unique data strengthen studies linking in utero exposures to altered DNA methylation by showing, for the first time, that such changes are present in fetal life and in a key metabolic target tissue, human fetal liver. Furthermore, these data propose a novel mechanism by which such changes are induced, namely through alterations in methyl donor availability and changes in 1-carbon metabolism.


Assuntos
Carbono/metabolismo , Metilação de DNA/efeitos dos fármacos , Feto/metabolismo , Fígado/metabolismo , Transferases de Grupo de Um Carbono/metabolismo , Fumar/efeitos adversos , Adulto , Peso Corporal , Cobalto/análise , Feminino , Humanos , Fator de Crescimento Insulin-Like II/genética , Fator de Crescimento Insulin-Like II/metabolismo , Fígado/química , Masculino , Transferases de Grupo de Um Carbono/genética , Gravidez , RNA Mensageiro/análise , Receptores de Glucocorticoides/metabolismo , Estudos Retrospectivos , Fatores Sexuais , Vitamina B 12/análise
17.
Chembiochem ; 16(17): 2498-506, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26374477

RESUMO

Nucleocidin is one of the very few natural products known to contain fluorine. Mysteriously, the nucleocidin producer Streptomyces calvus ATCC 13382 has not been observed to synthesize the compound since its discovery in 1956. Here, we report that complementation of S. calvus ATCC 13382 with a functional bldA-encoded Leu-tRNA(UUA) molecule restores the production of nucleocidin. Nucleocidin was detected in culture extracts by (19) F NMR spectroscopy, HPLC-ESI-MS, and HPLC-continuum source molecular absorption spectroscopy for fluorine-specific detection. The molecule was purified from a large-scale culture and definitively characterized by NMR spectroscopy and high-resolution MS. The nucleocidin biosynthetic gene cluster was identified by the presence of genes encoding the 5'-O-sulfamate moiety and confirmed by gene disruption. Two of the genes within the nucleocidin biosynthetic gene cluster contain TTA codons, thus explaining the dependence on bldA and resolving a 60-year-old mystery.


Assuntos
Adenosina/análogos & derivados , Proteínas de Bactérias/metabolismo , Produtos Biológicos/metabolismo , RNA de Transferência de Leucina/metabolismo , Streptomyces/metabolismo , Adenosina/análise , Adenosina/biossíntese , Adenosina/química , Proteínas de Bactérias/genética , Produtos Biológicos/análise , Produtos Biológicos/química , Cromatografia Líquida de Alta Pressão , Flúor/química , Halogenação , Espectrometria de Massas , Família Multigênica , Fases de Leitura Aberta/genética , Purina-Núcleosídeo Fosforilase/genética , Purina-Núcleosídeo Fosforilase/metabolismo , RNA de Transferência de Leucina/genética , Streptomyces/genética
18.
PLoS Pathog ; 9(10): e1003676, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24146619

RESUMO

Nutritional immunity--the withholding of nutrients by the host--has long been recognised as an important factor that shapes bacterial-host interactions. However, the dynamics of nutrient availability within local host niches during fungal infection are poorly defined. We have combined laser ablation-inductively coupled plasma mass spectrometry (LA-ICP MS), MALDI imaging and immunohistochemistry with microtranscriptomics to examine iron homeostasis in the host and pathogen in the murine model of systemic candidiasis. Dramatic changes in the renal iron landscape occur during disease progression. The infection perturbs global iron homeostasis in the host leading to iron accumulation in the renal medulla. Paradoxically, this is accompanied by nutritional immunity in the renal cortex as iron exclusion zones emerge locally around fungal lesions. These exclusion zones correlate with immune infiltrates and haem oxygenase 1-expressing host cells. This local nutritional immunity decreases iron availability, leading to a switch in iron acquisition mechanisms within mature fungal lesions, as revealed by laser capture microdissection and qRT-PCR analyses. Therefore, a complex interplay of systemic and local events influences iron homeostasis and pathogen-host dynamics during disease progression.


Assuntos
Candida albicans/imunologia , Candidíase/imunologia , Ferro/imunologia , Animais , Candida albicans/metabolismo , Candidíase/metabolismo , Candidíase/patologia , Modelos Animais de Doenças , Feminino , Ferro/metabolismo , Rim/imunologia , Rim/metabolismo , Rim/patologia , Camundongos , Camundongos Endogâmicos BALB C
19.
Anal Bioanal Chem ; 407(3): 973-81, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25318461

RESUMO

Mercury (Hg) is a global pollutant which occurs in different species, with methylmercury (MeHg) being the critical compound due to its neurotoxicity and bioaccumulation through the food chain. Methods for trace speciation of MeHg are therefore needed for a vast range of sample matrices, such as biological tissues, fluids, soils or sediments. We have previously developed an ultra-trace speciation method for methylmercury in water, based on a preconcentration HPLC cold vapour atomic fluorescence spectrometry (HPLC-CV-AFS) method. The focus of this work is mercury speciation in a variety of sample matrices to assess the versatility of the method. Certified reference materials were used where possible, and samples were spiked where reference materials were not available, e.g. human urine. Solid samples were submitted for commonly used digestion or extraction processes to obtain a liquid sample for injection into the analytical system. For MeHg in sediment samples, an extraction procedure was adapted to accommodate MeHg separation from high amounts of Hg(2+) to avoid an overload of the column. The recovery for MeHg determination was found to be in the range of 88-104% in fish reference materials (DOLT-2, DOLT-4, DORM-3), lobster (TORT-2), seaweed (IAEA-140/TM), sediments (ERM(®)-CC580) and spiked urine and has been proven to be robust, reliable, virtually matrix-independent and relatively cost-effective. Applications in the ultra-trace concentration range are possible using the preconcentration up to 200 mL, while for higher MeHg-containing samples, lower volumes can be applied. A comparison was carried out between species-specific isotope dilution gas chromatography inductively coupled plasma mass spectrometry (SSID-GC-ICP-MS) as the gold standard and HPLC-CV-AFS for biological tissues (liver, kidney and muscle of pilot whales), showing a slope of 1.008 and R (2) = 0.97, which indicates that the HPLC-CV-AFS method achieves well-correlated results for MeHg in biological tissues.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Sedimentos Geológicos/análise , Compostos de Metilmercúrio/análise , Espectrometria de Fluorescência/métodos , Animais , Organismos Aquáticos , Cromatografia Líquida de Alta Pressão/instrumentação , Desenho de Equipamento , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Limite de Detecção , Compostos de Metilmercúrio/urina , Sistemas On-Line , Técnica de Diluição de Radioisótopos , Alga Marinha/química , Baleias
20.
Anal Chem ; 86(2): 993-9, 2014 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-24354293

RESUMO

Because of the toxicity of inorganic arsenic (iAs), only iAs needs to be monitored in food and feedstuff. This demands the development of easy and quick analytical methods to screen large number of samples. This work focuses on hydride generation (HG) coupled with an ICPMS as an arsenic detector where the HG is added as a selective step to determine iAs in the gaseous phase while organically bound As remains in the solution. iAs forms volatile arsine species with high efficiency when treated with NaBH4 at acidic conditions, whereas most other organoarsenic compounds do not form any or only less volatile arsines. Additionally, using high concentrations of HCl further reduces the production of the less volatile arsines and iAs is almost exclusively formed, therefore enabling to measure iAs without a prior step of species separation using chromatography. Here, we coupled a commercially available HG system to an ICPMS and optimized for determination of iAs in rice and samples of marine origin using different acid concentrations, wet and dry plasma conditions, and different reaction gas modes. Comparing this method to conventional HPLC-ICPMS, no statistical difference in iAs concentration was found and comparable limits of detections were achieved using less than half the instrument time.

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