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1.
Nat Commun ; 12(1): 366, 2021 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-33446657

RESUMO

Many tumour cells show dependence on exogenous serine and dietary serine and glycine starvation can inhibit the growth of these cancers and extend survival in mice. However, numerous mechanisms promote resistance to this therapeutic approach, including enhanced expression of the de novo serine synthesis pathway (SSP) enzymes or activation of oncogenes that drive enhanced serine synthesis. Here we show that inhibition of PHGDH, the first step in the SSP, cooperates with serine and glycine depletion to inhibit one-carbon metabolism and cancer growth. In vitro, inhibition of PHGDH combined with serine starvation leads to a defect in global protein synthesis, which blocks the activation of an ATF-4 response and more broadly impacts the protective stress response to amino acid depletion. In vivo, the combination of diet and inhibitor shows therapeutic efficacy against tumours that are resistant to diet or drug alone, with evidence of reduced one-carbon availability. However, the defect in ATF4-response seen in vitro following complete depletion of available serine is not seen in mice, where dietary serine and glycine depletion and treatment with the PHGDH inhibitor lower but do not eliminate serine. Our results indicate that inhibition of PHGDH will augment the therapeutic efficacy of a serine depleted diet.


Assuntos
Glicina/metabolismo , Neoplasias/dietoterapia , Serina/biossíntese , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Glicina/análise , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/enzimologia , Neoplasias/metabolismo , Neoplasias/fisiopatologia , Fosfoglicerato Desidrogenase/metabolismo , Serina/análise
2.
Chemosphere ; 262: 128327, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182089

RESUMO

The globally used herbicide glyphosate and its metabolite aminomethylphosphonic acid (AMPA) have not yet been reported to occur in the marine environment, presumably due to a lack of suitable analytical methods. In this study, we developed two new methods for the analysis of glyphosate and AMPA in seawater: a small-scale method, which includes an SPE cleanup step that minimizes salt-matrix effects during LC-MS/MS analysis, and a large-scale method that employs an additional SPE preconcentration step. Different SPE materials were evaluated for their suitability to enrich glyphosate and AMPA from saltwater and a molecularly imprinted polymer was selected. Both methods were validated in ultrapure water and environmental seawater. Achieved limits of detection with the small-scale method were 6 and 8 ng/L for glyphosate and AMPA, while the large-scale method achieved 0.12 and 0.22 ng/L, respectively. The small-scale method was used to analyze environmental samples from the Warnow Estuary in Germany. Glyphosate and AMPA could be successfully detected in the samples, but could not be measured beyond the saline estuary due to dilution and degradation effects. A set of samples from the western Baltic Sea was analyzed with the large-scale method. Glyphosate and AMPA could be detected in all Baltic Sea samples, especially at stations close to estuaries. To the best of our knowledge, this is the first report on the occurrence of glyphosate and AMPA in seawater.


Assuntos
Monitoramento Ambiental/métodos , Glicina/análogos & derivados , Herbicidas/análise , Organofosfonatos/análise , Água do Mar/química , Poluentes Químicos da Água/análise , Cromatografia Líquida/métodos , Estuários , Alemanha , Glicina/análise , Limite de Detecção , Oceanos e Mares , Espectrometria de Massas em Tandem/métodos
3.
Food Chem ; 338: 128133, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33091994

RESUMO

Glyphosate (GLYP) was the most widely used broad-spectrum herbicide in the world. Herein, a gold nanoparticle (AuNP) probe dual-functionalized with anti-GLYP antibody and double-stranded oligonucleotides was synthesized. An AuNP-based bio-barcode immuno-PCR (AuNP-BB-iPCR) based on the probe was developed for sensitive detection of GLYP in food samples without high-cost and time-consuming experiments. GLYP detection was accomplished with a linear range from 61.1 pg g-1 to 31.3 ng g-1 and a detection limit of 4.5 pg g-1 which was 7 orders of magnitude lower than that of conventional ELISA (70 µg g-1) developed using the same antibody. The recoveries of GLYP from soybean, cole and maize samples were 99.8%, 102.6% and 103.7%, respectively, and all relative standard deviation values were below 12.9%. The assay time (including food samples preparation) of AuNP-BB-iPCR was 4 h. The proposed AuNP-BB-iPCR exhibits potential for sensitive detection of GLYP in foodstuffs and environment.


Assuntos
Glicina/análogos & derivados , Ouro/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Reação em Cadeia da Polimerase/métodos , Glicina/análise , Glicina/química , Humanos
4.
Environ Health ; 19(1): 115, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33183283

RESUMO

BACKGROUND: Glyphosate, a commonly used pesticide, has been the topic of much debate. The effects of exposure to glyphosate remains a contentious topic. This paper provides an update to the existing literature regarding levels of glyphosate exposure in occupationally exposed individuals and focuses or reviewing all the available published literature regarding glyphosate exposure levels in children. METHODS: A literature review was conducted and any articles reporting quantifiable exposure levels in humans published since January 2019 (the last published review on glyphosate exposure) were reviewed and data extracted and standardized. RESULTS: A total of five new studies reporting exposure levels in humans were found including 578 subjects. Two of these studies focused on occupationally exposed individuals while three of them focused on glyphosate exposure levels in children. Given the sparse nature of the new data, previously identified studies on exposure to glyphosate in children were included in our analysis of children's exposure. The lowest average level of glyphosate exposure reported was 0.28 µg/L and the highest average exposure levels reported was 4.04 µg/L. CONCLUSION: The literature on glyphosate exposure levels, especially in children, remains limited. Without more data collected in a standardized way, parsing out the potential relationship between glyphosate exposure and disease will not be possible.


Assuntos
Glicina/análogos & derivados , Herbicidas/análise , Exposição Ocupacional/análise , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Glicina/análise , Humanos , Lactente , Recém-Nascido , Masculino , Adulto Jovem
5.
J Chromatogr A ; 1632: 461603, 2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33099238

RESUMO

The herbicide glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) are generally studied in environmental samples in the investigation of contamination of soil, plants, water and food. Many analytical methods are based on liquid chromatography or high-performance liquid chromatography, with pre-column or post-column derivatization; in addition, the chromatograph can be coupled to mass spectrometers for detection and quantification. Gas chromatography and spectroscopic and electrochemical methods have also been used. In this work, a simple low-cost method is presented for the analysis of water intended for human consumption with the quantification not only of glyphosate and AMPA, but also of other ions of interest to public health (fluoride, chlorite, bromate, chloride, nitrite, nitrate, sulfate and phosphate). Based on ion chromatography with conductivity detection (chemical suppression of eluent conductivity), the key point in this method is the use of gradient elution with two eluents of different pH and ionic strength, not requiring derivatization. There is no interference from the other ions at higher concentrations. The detection limits obtained for glyphosate and AMPA were 15 µg L-1 and 80 µg L-1, respectively. As the method allows the analysis of a large number of samples, it has been successfully applied to monitoring the quality of tap water in 89 municipalities in the northeast region of the State of São Paulo, Brazil.


Assuntos
Cromatografia por Troca Iônica/métodos , Água Potável/química , Monitoramento Ambiental/métodos , Glicina/análogos & derivados , Saúde Pública , Poluentes Químicos da Água/análise , Glicina/análise , Herbicidas/análise , Humanos , Limite de Detecção , Compostos Organofosforados/química , Padrões de Referência , Soluções
6.
J Environ Sci Health B ; 55(10): 909-920, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33084505

RESUMO

Glyphosate is the main herbicide used in soybean crops, and Brazil is one of the major soybean producers around the world. GLY and AMPA were evaluated in 124 surface waters samples of twenty one micro basins in Paraná Basin 3 (State of Parana, Brazil) over six subsequent weeks. A simple and economical routine methodology was established, based on lyophilization as a pre-concentration method. The validated method showed a limit of detection of 0.0125 and 0.025 µg L-1 for GLY and AMPA, respectively. In general, water samples presented concentrations ranging from 0.31 to 1.65 µg L-1 for GLY. Those values are below the maximum allowed amounts in Brazilian Law (65 µg L-1). The AMPA values were found in the range from 0.50 to 1.40 µg L-1. In summary, GLY was detected in 19.3% and it was quantified in 17.7% of the samples. AMPA was detected in 21.8% and it was quantified in 1.6% of the samples. Although samples did not present values higher than the established by Brazilian Law, GLY and AMPA appear constantly in the samples, which highlight the importance of monitoring studies in watersheds.


Assuntos
Água Doce/análise , Glicina/análogos & derivados , Herbicidas/análise , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análise , Brasil , Cromatografia Líquida de Alta Pressão , Fluorescência , Liofilização , Glicina/análise
7.
Bull Environ Contam Toxicol ; 105(1): 95-102, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32537734

RESUMO

Differential pulse polarographic (DPP) investigations on the reaction of the amino function of glyphosate and glufosinate herbicides with carbon disulphide and copper(II) perchlorate forming copper(III) dithiocarbamate complexes were made in the presence of sodium perchlorate in acetonitrile at dropping mercury electrode (DME). The newly formed herbicide complexes exhibited analytically useful diffusion-controlled peaks at - 115 mV and - 110 mV versus saturated calomel electrode (SCE) with linear relationship between current and concentration. This observation formed the basis for the determination of glyphosate and glufosinate in the concentration ranges 0.34-8.45 µg mL-1 and 0.4-9.91 µg mL-1 respectively with correlation coefficient of 0.999. The method was applied to their determinations in soil, fortified food and spiked water samples to assess their environmental relevance. The recoveries of the herbicides were in the range 89.5%-98.3% with relative standard deviation (RSD) in the ranges 0.8%-1.8% thus showing good accuracy and precision of the method.


Assuntos
Monitoramento Ambiental , Glicina/análogos & derivados , Herbicidas/análise , Aminobutiratos , Glicina/análise , Solo
8.
Ecotoxicol Environ Saf ; 201: 110821, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32544746

RESUMO

Primary production (PP) is a key variable to evaluate the quality of the ecological services provided by freshwater bodies because it gives information on the amount of oxygen and organic matter incorporated into the system. We analysed the impact of a mixture of commercial formulations of glyphosate- and 2,4-D-based herbicides (Roundup Max® and AsiMax 50®, respectively) on freshwater primary production. Primary production was studied through the oxygen exchange method. Four measurements were made during a 23-day experiment in outdoor mesocosms using the light and dark bottle method. High and low concentrations of the active ingredients were assayed to evaluate a concentration-dependent effect. Our results indicated that the mixture of Roundup Max® and AsiMax 50® acted mostly additively on gross and net primary production. Moreover, we found a concentration-dependent effect of each herbicide on PP. Thus, AsiMax 50® at low and Roundup Max® at high concentration induced a significant early decrease in respiration and gross primary production 4 h after application, attributable to physiological responses. Besides, significant increases in primary production were simultaneously recorded with increases in chlorophyll a concentration and micro + nano-phytoplankton abundance 7 days after the application of Roundup Max® at high concentration. This study contributes to the knowledge of the impact of widely used herbicides on freshwater ecosystems.


Assuntos
Água Doce/química , Herbicidas/toxicidade , Microbiota/efeitos dos fármacos , Fitoplâncton/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Ácido 2,4-Diclorofenoxiacético/análise , Ácido 2,4-Diclorofenoxiacético/toxicidade , Animais , Clorofila A/metabolismo , Relação Dose-Resposta a Droga , Água Doce/análise , Glicina/análogos & derivados , Glicina/análise , Glicina/toxicidade , Herbicidas/análise , Fitoplâncton/metabolismo , Poluentes Químicos da Água/análise
9.
J Environ Sci Health B ; 55(9): 794-802, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32586204

RESUMO

Herbicide use, mainly glyphosate, has been intense in worldwide agriculture, including in the Brazilian Amazon region. This study aimed to validate a method for determining glyphosate and its degradation product, AMPA, and glufosinate by HPLC-FL in 58 water samples collected at the Santarém plateau region (Planalto Santareno), in the western of Pará state, Brazil. The method involves filtration and direct injection in the HPLC-FL for AMPA analysis, or previous concentration (10×) by lyophilization for glufosinate and glyphosate analysis. Analytes were oxidized and complexed with o-phthalaldehyde and 2-mercaptoethanol in a post-column reaction before fluorescence detection. LOQs for AMPA, glyphosate and glufosinate were established at 0.5, 0.2 and 0.3 µg L-1, respectively. A total of 58 samples were collected. Glyphosate and glufosinate were not detected in any of the 30 surface water samples collected in 2015 (

Assuntos
Aminobutiratos/análise , Cromatografia Líquida de Alta Pressão/métodos , Glicina/análogos & derivados , Poluentes Químicos da Água/análise , Água/química , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análise , Brasil , Monitoramento Ambiental , Fluorescência , Liofilização , Glicina/análise , Herbicidas/análise , Limite de Detecção , Reprodutibilidade dos Testes
10.
Food Chem ; 327: 127013, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454275

RESUMO

As a subtropical fruit with high commercial values, litchi is also a source of methylenecyclcopropylglycine (MCPG) and hypoglycin A (HGA), which could cause hypoglycemia and fatal encephalopathy in human. In this work, a quantitative method was developed well to detect MCPG and HGA present in litchi aril of different cultivars. Method validation was evaluated well by linearity, recovery, precision and sensitivity. Among three cultivars, 'Feizixiao' contained the highest toxin level with 0.60-0.83 mg kg-1 of MCPG and 10.66-14.46 mg kg-1 of HGA, followed by 'Huaizhi' with 0.08-0.12 mg kg-1 of MCPG and 0.63-1.54 mg kg-1 of HGA, and 'Nuomici' with 0.09-0.11 mg kg-1 of MCPG and 0.35-0.91 mg kg-1 of HGA. The toxin levels were highly associated with litchi cultivar and storage time. These findings can provide new knowledge to help to recommend the safe consumption of fresh litchi based on human health.


Assuntos
Ciclopropanos/análise , Análise de Alimentos/métodos , Glicina/análogos & derivados , Hipoglicinas/análise , Litchi/química , China , Cromatografia Líquida de Alta Pressão , Frutas/química , Glicina/análise , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
11.
Ecotoxicol Environ Saf ; 196: 110501, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247958

RESUMO

In this work we analyzed the effects of Sulfosato Touchdown®, a glyphosate-based herbicide, on the ontogenic development and biochemical markers of the freshwater copepod Notodiaptomus carteri. A 30-days life-cycle experiment was carried out with three different glyphosate concentrations (0, 0.38, and 0.81 mg L-1) to analyze the developmental time from nauplii to adult copepods and their individual growth. An additional 10-days experiment with the same glyphosate concentrations was designed to evaluate the energy reserves (glycogen, proteins and lipids) and the activity of three antioxidant enzymes, superoxide dismutase (SOD), catalase, and glutathione-S-transferase (GST) in adult copepods, separately for females and males. We found that the lowest glyphosate concentration increased the nauplii and total development time. The highest glyphosate concentration prevented copepods from reaching the adult stage, inhibited the growth of the first copepodite stage and increased the GST and SOD activity in adult females. According to our results, the presence of this herbicide in freshwater systems could impose a risk in the ecological role of copepods in nature. This study will contribute to propose the Notodiaptomus genus as model specie for monitoring purposes in the Neotropical aquatic systems.


Assuntos
Copépodes/efeitos dos fármacos , Biomarcadores Ambientais/efeitos dos fármacos , Água Doce/química , Glicina/análogos & derivados , Herbicidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Catalase/metabolismo , Copépodes/enzimologia , Copépodes/crescimento & desenvolvimento , Feminino , Glutationa Transferase/metabolismo , Glicina/análise , Glicina/toxicidade , Herbicidas/análise , Masculino , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/análise
12.
PLoS One ; 15(3): e0230646, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32208468

RESUMO

Pesticides, widely used in modern agriculture, could potentially cause environmental pollution and affect human lives. Hence, the development of a highly sensitive sensing element to detect pesticide residues is crucial for food safety and ecosystem protection. Optical methods based on fluorescence properties provide an ideal approach for screening and quantification of these compounds in different medias including water, plant, and nutritional products. The development of fluorescence emitting carbon dot-based sensors for monitoring pesticides has attracted great attention in recent years. In comparison to other fluorophores, carbon dots have more promising optical features, higher quantum yields and better biocompatibility. This article aims to present a novel fluorescent sensing method of diazinon, glyphosate, and amicarbazone using plant-based carbon dots. A comprehensive characterization of carbon dots obtained from cauliflower was performed by methods including UV-visible, FTIR spectroscopy, fluorometry, AFM, DLS, and zeta sizer. Following this step, carbon dots were used to detect pesticides. The fluorescence quenching property of carbon dots has been utilized to identify detection limit of 0.25, 0.5, and 2 ng ml-1 for diazinon, amicarbazone, and glyphosate, respectively. Also, real sample study revealed that the detection of pesticides accompanied by our developed nano-sensor is repeatable and accurate. According to carbon dots specificity determination, the prepared nano sensor does not have the potential to identify "bromacil" and "dialen super" pesticides but the other three mentioned pesticides are detectable. The results confirm that synthesized green carbon dots are well qualified for application in food safety and environmental monitoring.


Assuntos
Carbono/química , Praguicidas/análise , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Diazinon/análise , Monitoramento Ambiental , Contaminação de Alimentos/análise , Glicina/análogos & derivados , Glicina/análise , Limite de Detecção , Lycopersicon esculentum/química , Lycopersicon esculentum/metabolismo , Triazóis/análise
13.
J Chromatogr A ; 1619: 460939, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32085912

RESUMO

Glyphosate (Glyp) and glufosinate (Gluf) are widely used herbicides around the world, and their effects on human health and detection of levels have drawn increasing attention. The present study was to establish a method to determine the contents of Glyp and Gluf from corn using multi-walled carbon nanotubes (MWCNTs) followed by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The corn samples were purified by MWCNTs, then the analytes reacted with 9-fluorenylmethylchloroformate (FMOCCl) of acetonitrile solution (20.0 g/L) at 50 °C water bath in a borate buffer solution (50.0 g/L, pH=9) to generate FMOC derivative products. After the derivatization, HSS T3 was used as the separation column, with acetonitrile and 0.05% ammonia as the mobile phase, and multiple reaction monitoring (MRM) mode with negative electrospray ionization (ESI-) was adopted. The validation parameters showed good verification results, with both of their quantitative limits (LOQ) as 0.005 mg/kg, recoveries between 90.3% and 95.4%, intra-day relative standard deviations (RSDs) in the ranges of 1.24% and 3.35%, and inter-day RSDs between 3.56% and 6.06%. The analytical method, developed in this study, has high accuracy and sensitivity, and is suitable for the simultaneous detection of Glyp and Gluf in corn.


Assuntos
Aminobutiratos/análise , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Glicina/análogos & derivados , Espectrometria de Massas em Tandem , Zea mays/química , Acetonitrilos/química , Fluorenos/química , Glicina/análise , Herbicidas/análise , Nanotubos de Carbono/química , Reprodutibilidade dos Testes
14.
J Environ Sci Health B ; 55(6): 558-565, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32107966

RESUMO

Glyphosate is the main herbicide currently used in the world due to wide applicability and efficiency in controlling weeds in many crops. However, its overuse may lead to undesirable impacts on the environment and to human health in the long run. This present study aimed to optimize and validate solid phase extraction (SPE) using an anionic resin for the simultaneous and direct determination of glyphosate and aminomethylphosphonic acid (AMPA) in water samples using high-performance liquid chromatography combined with inductively coupled plasma with triple quadrupole mass spectrometer (HPLC-ICP-MS/MS). The results showed that recovery percentage and relative standard deviation were 103.9 ± 7.9 and 99.40 ± 9.9% for glyphosate and AMPA, respectively. The validation certified that the method was precise, accurate, linear, and selective, with a limit of quantification of 1.09 and 0.29 µg L-1 for glyphosate and AMPA, respectively. The optimized methodology reached the concentration factor of 250 times and was successfully applied to analyze water samples from hydroponic cultivation of the eucalyptus seedlings. The results showed that the exudation process occurs at glyphosate doses starting from 2 L ha-1.


Assuntos
Eucalyptus/crescimento & desenvolvimento , Glicina/análogos & derivados , Isoxazóis/química , Tetrazóis/química , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão/métodos , Glicina/análise , Glicina/isolamento & purificação , Herbicidas/análise , Hidroponia , Limite de Detecção , Reprodutibilidade dos Testes , Plântula/crescimento & desenvolvimento , Extração em Fase Sólida , Espectrometria de Massas em Tandem/métodos
15.
Sci Rep ; 10(1): 697, 2020 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959821

RESUMO

Pellicle is the initial proteinaceous layer that is formed almost instantaneously on all solid surfaces in the oral cavity. It is of essential relevance for any interactions and metabolism on the tooth surface. Up to now, there is no information on the metabolome of this structure. Accordingly, the present study aims to characterise the metabolomic profile of in-situ pellicle in children with different caries activity for the first time in comparison to saliva. Small molecules such as carbohydrates, amino acids, organic acids, and fatty acids, putatively involved in the formation of caries were quantified using mass spectrometry (MS)-based techniques, such as (stable isotope dilution analysis)-ultra-performance liquid chromatography-tandem MS and gas chromatography/electron ionisation-MS. Pellicle and corresponding saliva samples were collected from caries-active, caries-free and caries-rehabilitated 4- to 6-year-old children. The most abundant analytes in pellicle were acetic acid (1.2-10.5 nmol/cm2), propionic acid (0.1-8.5 nmol/cm2), glycine (0.7-3.5 nmol/cm2), serine (0.08-2.3 nmol/cm2), galactose (galactose + mannose; 0.035-0.078 nmol/cm2), lactose (0.002-0.086 nmol/cm2), glucose (0.018-0.953 nmol/cm2), palmitic acid (0.26-2.03 nmol/cm2), and stearic acid (0.34-1.81 nmol/cm2). Significant differences depending on caries activity were detected neither in saliva nor in the corresponding pellicle samples.


Assuntos
Cárie Dentária/metabolismo , Película Dentária/química , Metabolômica/métodos , Saliva/química , Ácido Acético/análise , Estudos de Casos e Controles , Criança , Pré-Escolar , Cromatografia Líquida , Glicina/análise , Humanos , Masculino , Propionatos/análise , Espectrometria de Massas em Tandem
16.
Rapid Commun Mass Spectrom ; 34(7): e8668, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-31961458

RESUMO

RATIONALE: Glyphosate is one of the most widely used herbicides and it is suspected to affect the intestinal microbiota through inhibition of aromatic amino acid synthesis via the shikimate pathway. In vitro microbiome bioreactors are increasingly used as model systems to investigate effects on intestinal microbiota and consequently methods for the quantitation of glyphosate and its degradation product aminomethylphosphonic acid (AMPA) in microbiome model systems are required. METHODS: An optimized protocol enables the analysis of both glyphosate and AMPA by simple extraction with methanol:acetonitrile:water (2:3:1) without further enrichment steps. Glyphosate and AMPA are separated by liquid chromatography on an amide column and identified and quantified with a targeted tandem mass spectrometry method using a QTRAP 5500 system (AB Sciex). RESULTS: Our method has a limit of detection (LOD) in extracted water samples of <2 ng/mL for both glyphosate and AMPA. In complex intestinal medium, the LOD is 2 and 5 ng/mL for glyphosate and AMPA, respectively. These LODs allow for measurement at exposure-relevant concentrations. Glyphosate levels in a bioreactor model of porcine colon were determined and consequently it was verified whether AMPA was produced by porcine gut microbiota. CONCLUSIONS: The method presented here allows quantitation of glyphosate and AMPA in complex bioreactor fluids and thus enables studies of the impact of glyphosate and its metabolism on intestinal microbiota. In addition, the extraction protocol is compatible with an untargeted metabolomics analysis, thus allowing one to look for other perturbations caused by glyphosate in the same sample.


Assuntos
Colo/microbiologia , Microbioma Gastrointestinal , Glicina/análogos & derivados , Herbicidas/análise , Compostos Organofosforados/análise , Animais , Reatores Biológicos , Microbioma Gastrointestinal/efeitos dos fármacos , Glicina/análise , Glicina/metabolismo , Herbicidas/metabolismo , Metabolômica , Compostos Organofosforados/metabolismo , Suínos , Espectrometria de Massas em Tandem
17.
Chemosphere ; 238: 124575, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31446274

RESUMO

Significance of surface and ground water contamination by synthetic organic compounds has been pointed out in a very high number of papers worldwide, as well as the need of application of treatment technologies capable to assure their complete removal. Among these processes, the electrochemical advanced oxidation is an interesting option, especially when irradiated with UVC light (photo-electrochemical, P-EC) to promote homolysis of electrogenerated oxidants. In this work, the herbicide glyphosate (GLP) was used as model compound and it was electrochemically treated under UVC irradiation in the presence of NaCl and using a DSA® and BDD anodes. Total organic carbon concentration was measured throughout the electrolysis, as well as the concentration of short chain carboxylic acids and inorganic ions (NO3-, PO43-,ClO-, ClO3- and ClO4-). The synergism of the P-EC was more pronounced when using a DSA® electrode, which led to complete GLP mineralization in 1 h (0.52 A h L-1), as also confirmed by the stoichiometric formation of NO3- and PO43- ions, with an energy consumption as low as 1.25 kW h g-1. Unexpectedly, the concentration evolution of oxyhalides for the P-EC process using both anodes, especially for DSA® at 10 mA cm-2, showed the production of ClO3-, whereas detection of ClO4- species was only found when using BDD at 100 mA cm-2 for the electrochemical process. Finally, small amounts of carboxylic acids were detected, including dichloroacetic acid, especially when using a BDD electrode.


Assuntos
Técnicas Eletroquímicas/métodos , Glicina/análogos & derivados , Água Subterrânea/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Purificação da Água/métodos , Ácidos Carboxílicos/análise , Diamante/química , Eletrodos , Glicina/análise , Oxidantes/química , Oxirredução , Raios Ultravioleta
19.
Talanta ; 207: 120344, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594624

RESUMO

Glyphosate (Gly) is the most widely used herbicide at the moment. It presents a broad spectrum of action, hence its use for many different crops. Regulatory agencies have constantly mentioned the low hazard potential of Gly to mammals. However, the International Agency for Research on Cancer concluded in 2015 that glyphosate is "probably carcinogenic to humans". For this reason, it is important to develop reliable analytical methods to quantify Gly in food samples. Here, we propose an analytical method that makes use of graphene quantum dots (GQDs) and cysteine-capped silver nanoparticles (AgNPs) for the screening of glyphosate, using QuEChERS as sample treatment. Gly quenched the luminescence of GQDs-AgNPs system, achieving an excellent sensitivity (detection limit of 9 ng mL-1) and selectivity. The method developed was applied to different types of pulses (peas and lupins), obtaining recoveries close to 100% and relative standard deviations lower than 4% in all cases. Its simplicity and rapidity make this method an interesting alternative to other existing methodologies for the analysis of this pesticide in food samples.


Assuntos
Análise de Alimentos/métodos , Glicina/análogos & derivados , Grafite/química , Substâncias Luminescentes/química , Nanopartículas Metálicas/química , Pontos Quânticos/química , Prata/química , Glicina/análise , Glicina/química , Limite de Detecção
20.
Food Chem ; 307: 125534, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31644980

RESUMO

There has been increasing recent concern about the agricultural use of organophosphorus pesticides. A rapid and sensitive fluorescence assay for the detection of three organophosphorus pesticides has therefore been developed using 6-carboxy-fluorescein labeling aptamer as the probe and functionalized magnetic nanoparticles as the separation carrier. The aptamer hybridized with complementary DNA conjugated on the surface of the magnetic nanoparticles to form a magnetic aptamer-complementary DNA complex. Upon introducing the target organophosphorus pesticide, the aptamer departed from the complementary DNA, resulting in the fluorescence signal. Under optimized conditions, the limits of detection (LODs, S/N = 3) for trichlorfon, glyphosate, and malathion were 72.20 ng L-1, 88.80 ng L-1, and 195.37 ng L-1, respectively. The method was applied for the detection of trichlorfon, glyphosate, and malathion in spiked lettuce and carrot samples. The recoveries were in the range of 79.4%-118.7%, which were in good agreement with those obtained by gas chromatography, and the relative standard deviations were also acceptable. The method therefore has high sensitivity, so provides a means for the detection of multiple organophosphorus pesticides.


Assuntos
Aptâmeros de Nucleotídeos/química , Nanopartículas , Compostos Organofosforados/análise , Praguicidas/análise , Espectrometria de Fluorescência , Cromatografia Gasosa , Daucus carota/química , Corantes Fluorescentes , Glicina/análogos & derivados , Glicina/análise , Alface/química , Limite de Detecção , Magnetismo , Malation/análise , Praguicidas/química , Triclorfon/análise
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