Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
1.
Toxins (Basel) ; 14(12)2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36548716

RESUMO

Aflatoxin contamination in corn is a significant issue, posing substantial health threats to humans and animals. Aflatoxin testing protects consumer health, ensures the safe global trade of corn, and verifies compliance with legislation; however, effective sampling procedures are essential to ensure reliable results. While many sampling procedures exist, there is no evidence to indicate which is the best approach to ensure accurate detection. Using scientific and gray literature sources, this review analyzed sampling procedures to determine an optimum approach to guide the development of standard practices. Results revealed that sampling is the major source of error in the accurate assessment of aflatoxin levels in food and crucial for obtaining reliable results. To guarantee low variability and sample bias-increased sample size and sampling frequency, the use of automatic dynamic sampling techniques, adequate storage, and homogenization of aggregate samples for analysis are advised to ensure a representative sample. However, there is a lack of evidence to support this or indicate the current utilization of the reviewed procedures. Inadequate data prevented the recommendation of sample sizes or frequency for optimum practice, and thus, further research is required. There is an urgent need to make sampling procedures fit-for-purpose to obtain accurate and reliable aflatoxin measurements.


Assuntos
Aflatoxinas , Humanos , Animais , Aflatoxinas/análise , Zea mays , Projetos de Pesquisa , Alimentos , Contaminação de Alimentos/análise
2.
Toxins (Basel) ; 14(10)2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-36287975

RESUMO

The contamination of animal feed with aflatoxins is an ongoing and growing serious issue, particularly for livestock farmers in tropical and subtropical regions. Exposure of animals to an aflatoxin-contaminated diet impairs feed efficiency and increases susceptibility to diseases, resulting in mortality, feed waste, and increased production costs. They can also be excreted in milk and thus pose a significant human health risk. This systematic review and network meta-analysis aim to compare and identify the most effective intervention to alleviate the negative impact of aflatoxins on the important livestock sector, poultry production. Eligible studies on the efficacy of feed additives to mitigate the toxic effect of aflatoxins in poultry were retrieved from different databases. Additives were classified into three categories based on their mode of action and composition: organic binder, inorganic binder, and antioxidant. Moreover, alanine transaminase (ALT), a liver enzyme, was the primary indicator. Supplementing aflatoxin-contaminated feeds with different categories of additives significantly reduces serum ALT levels (p < 0.001) compared with birds fed only a contaminated diet. Inorganic binder (P-score 0.8615) was ranked to be the most efficient in terms of counteracting the toxic effect of aflatoxins, followed by antioxidant (P-score 0.6159) and organic binder (P-score 0.5018). These findings will have significant importance for farmers, veterinarians, and animal nutrition companies when deciding which type of additives to use for mitigating exposure to aflatoxins, thus improving food security and the livelihoods of smallholder farmers in developing countries.


Assuntos
Aflatoxinas , Humanos , Animais , Aflatoxinas/toxicidade , Aflatoxinas/análise , Antioxidantes/análise , Metanálise em Rede , Alanina Transaminase , Contaminação de Alimentos/prevenção & controle , Contaminação de Alimentos/análise , Ração Animal/análise , Aves Domésticas
3.
Toxins (Basel) ; 14(8)2022 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-36006229

RESUMO

Raw feed materials are often contaminated with mycotoxins, and co-occurrence of mycotoxins occurs frequently. A total of 250 samples i.e., rice bran and maize from Cambodia, Laos, Myanmar, and Thailand were analysed using state-of-the-art liquid chromatography-mass spectrometry (LC-MS/MS) for monitoring the occurrence of regulated, emerging, and masked mycotoxins. Seven regulated mycotoxins - aflatoxins, ochratoxin A, fumonisin B1, deoxynivalenol, zearalenone, HT-2, and T-2 toxin were detected as well as some emerging mycotoxins, such as beauvericin, enniatin type B, stachybotrylactam, sterigmatocystin, and masked mycotoxins, specifically zearalenone-14-glucoside, and zearalenone-16-glucoside. Aspergillus and Fusarium mycotoxins were the most prevalent compounds identified, especially aflatoxins and fumonisin B1 in 100% and 95% of samples, respectively. Of the emerging toxins, beauvericin and enniatin type B showed high occurrences, with more than 90% of rice bran and maize contaminated, whereas zearalenone-14-glucoside and zearalenone-16-glucoside were found in rice bran in the range of 56-60%. Regulated mycotoxins (DON and ZEN) were the most frequent mycotoxin combination with emerging mycotoxins (BEA and ENN type B) in rice bran and maize. This study indicates that mycotoxin occurrence and co-occurrence are common in raw feed materials, and it is critical to monitor mycotoxin levels in ASEAN's feedstuffs so that mitigation strategies can be developed and implemented.


Assuntos
Aflatoxinas , Micotoxinas , Oryza , Zearalenona , Aflatoxinas/análise , Sudeste Asiático , Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Glucosídeos , Micotoxinas Mascaradas , Micotoxinas/análise , Espectrometria de Massas em Tandem/métodos , Zea mays , Zearalenona/análise
4.
J Fungi (Basel) ; 7(11)2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34829252

RESUMO

Seven agronomic factors (crop season, farming system, harvest date, moisture, county, oat variety, and previous crop) were recorded for 202 oat crops grown across Ireland, and samples were analysed by LC-MS/MS for four major Fusarium mycotoxins: deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin and HT-2 toxin. Type A trichothecenes were present in 62% of crops, with 7.4% exceeding European regulatory limits. DON (6.4%) and ZEN (9.9%) occurrences were relatively infrequent, though one and three samples were measured over their set limits, respectively. Overall, the type of farming system and the previous crop were the main factors identified as significantly influencing mycotoxin prevalence or concentration. Particularly, the adherence to an organic farming system and growing oats after a previous crop of grass were found to decrease contamination by type A trichothecenes. These are important findings and may provide valuable insights for many other types of cereal crops as Europe moves towards a much greater organic-based food system.

5.
Toxins (Basel) ; 12(7)2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32630277

RESUMO

Several studies have reported a wide range of severe health effects as well as clinical signs, when livestock animals are exposed to high concentration of mycotoxins. However, little is known regarding health effects of mycotoxins at low levels. Thus, a long-term feeding trial (between May 2017 and December 2019) was used to evaluate the effect of low doses of mycotoxin mixtures on performance of broiler chickens fed a naturally contaminated diet. In total, 18 successive broiler performance trials were carried out during the study period, with approximately 2200 one-day-old Ross-308 chicks used for each trial. Feed samples given to birds were collected at the beginning of each trial and analysed for multi-mycotoxins using a validated LC-MS/MS method. Furthermore, parameters including feed intake, body weight and feed efficiency were recorded on a weekly basis. In total, 24 mycotoxins were detected in samples analysed with deoxynivalenol (DON), zearalenone (ZEN), fumonisins (FBs), apicidin, enniatins (ENNs), emodin and beauvericin (BEV), the most prevalent mycotoxins. Furthermore, significantly higher levels (however below EU guidance values) of DON, ZEN, FBs, BEV, ENNs and diacetoxyscirpenol (DAS) were detected in 6 of the 18 performance trials. A strong positive relationship was observed between broilers feed efficiency and DON (R2 = 0.85), FBs (R2 = 0.53), DAS (R2 = 0.86), ZEN (R2 = 0.92), ENNs (R2 = 0.60) and BEV (R2 = 0.73). Moreover, a three-way interaction regression model revealed that mixtures of ZEN, DON and FBs (p = 0.01, R2 = 0.84) and ZEN, DON and DAS (p = 0.001, R2 = 0.91) had a statistically significant interaction effect on the birds' feed efficiency. As farm animals are often exposed to low doses of mycotoxin mixtures (especially fusarium mycotoxins), a cumulative risk assessment in terms of measuring and mitigating against the economic, welfare and health impacts is needed for this group of compounds.


Assuntos
Ração Animal/microbiologia , Ração Animal/toxicidade , Galinhas/crescimento & desenvolvimento , Microbiologia de Alimentos , Fungos/metabolismo , Micotoxinas/toxicidade , Animais , Micotoxinas/análise , Medição de Risco , Fatores de Tempo
6.
Toxins (Basel) ; 11(11)2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31726774

RESUMO

Contamination of animal feed with multiple mycotoxins is an ongoing and growing issue, as over 60% of cereal crops worldwide have been shown to be contaminated with mycotoxins. The present study was carried out to assess the efficacy of commercial feed additives sold with multi-mycotoxin binding claims. Ten feed additives were obtained and categorised into three groups based on their main composition. Their capacity to simultaneously adsorb deoxynivalenol (DON), zearalenone (ZEN), fumonisin B1 (FB1), ochratoxin A (OTA), aflatoxin B1 (AFB1) and T-2 toxin was assessed and compared using an in vitro model designed to simulate the gastrointestinal tract of a monogastric animal. Results showed that only one product (a modified yeast cell wall) effectively adsorbed more than 50% of DON, ZEN, FB1, OTA, T-2 and AFB1, in the following order: AFB1 > ZEN > T-2 > DON > OTA > FB1. The remaining products were able to moderately bind AFB1 (44-58%) but had less, or in some cases, no effect on ZEN, FB1, OTA and T-2 binding (<35%). It is important for companies producing mycotoxin binders that their products undergo rigorous trials under the conditions which best mimic the environment that they must be active in. Claims on the binding efficiency should only be made when such data has been generated.


Assuntos
Ração Animal/análise , Contaminação de Alimentos/análise , Micotoxinas/análise , Produtos Agrícolas/química , Técnicas In Vitro
7.
Food Chem ; 301: 125281, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31382109

RESUMO

The need for safe and quality food, free from the presence of hazardous contaminants such as mycotoxins is an on-going and complex challenge. Cold atmospheric pressure plasma (CAPP) has the potential to contribute to achieving this goal. Decontamination efficacy of CAPP against six of the most common mycotoxins found in foods and feedstuffs was assessed herein. Concentration reduction of up to 66% was achieved in maize for both aflatoxin B1 and fumonisin B1. Degradation products were detected only in the case of aflatoxin B1 and zearalenone and were tested on human hepatocarcinoma cells with no increase in cytotoxicity observed. Analysis of treated maize revealed substantial changes to small molecular mass components of the matrix. While CAPP shows promise in terms of mycotoxin detoxification important questions concerning potential changes to the nutritional and safety status of the food matrix require further investigations.


Assuntos
Descontaminação/métodos , Contaminação de Alimentos/análise , Micotoxinas/química , Gases em Plasma/química , Aflatoxina B1/análise , Aflatoxina B1/química , Aflatoxina B1/toxicidade , Fumonisinas/análise , Fumonisinas/química , Fumonisinas/toxicidade , Células Hep G2 , Hepatócitos/efeitos dos fármacos , Humanos , Micotoxinas/análise , Micotoxinas/toxicidade , Zea mays/química , Zearalenona/análise , Zearalenona/química , Zearalenona/toxicidade
8.
Food Chem Toxicol ; 121: 527-540, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30253246

RESUMO

As human co-exposure to natural toxins through food and water is inevitable, risk assessments to safeguard health are necessary. Aflatoxin B1 and fumonisin B1, frequent co-contaminants of maize and microcystin-LR, produced in freshwater by cyanobacteria are all naturally occurring potent toxins that threaten human health. Populations in the poorest regions of the world may suffer repeated simultaneous exposure to these contaminants. Using High Content Analysis, multiple cytotoxicity endpoints were measured for the individual toxins and mixtures in various cell lines. Results highlighted that significant cytotoxic effects were observed for aflatoxin B1 in all cell lines while no cytotoxic effects were observed for fumonisin B1 or microcystin-LR. Aflatoxin B1/microcystin-LR was cytotoxic in the order HepG2 > Caco-2 > MDBK. Fumonisin B1/microcystin-LR affected MDBK cells. The ternary mixture was cytotoxic to all cell lines. Most combinations were additive, however antagonism was observed for binary and ternary mixtures in HepG2 and MDBK cell lines at low and high concentrations. Synergy was observed in all cell lines, including at low concentrations. The combination of these natural toxins may pose a significant risk to populations in less developed countries. Furthermore, the study highlights the complexity around trying to regulate for human exposure to multiple contaminants.


Assuntos
Aflatoxina B1/toxicidade , Fumonisinas/toxicidade , Microcistinas/toxicidade , Aflatoxina B1/administração & dosagem , Aflatoxina B1/química , Animais , Biomarcadores/urina , Bovinos , Linhagem Celular , Relação Dose-Resposta a Droga , Contaminação de Alimentos , Fumonisinas/administração & dosagem , Fumonisinas/química , Humanos , Toxinas Marinhas , Microcistinas/administração & dosagem , Microcistinas/química , Toxinas Biológicas
9.
Sci Rep ; 8(1): 4913, 2018 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-29559706

RESUMO

Harmful Algal Blooms (HABs) in freshwater systems and intensified aquaculture have increased the risk to human health through exposure to cyanotoxins such as microcystin-LR (MC-LR). To understand the uptake and processing of MC-LR in humans, the pig was chosen as an animal model. This was assessed by repeated exposure for 13 weeks of eight animals dosed daily with MC-LR at 0.04 µg/kg bw, repeated with six animals over five weeks at a dose 50 times higher at 2 µg/kg bw. An analytical method was developed for MC-LR in porcine serum and also to analyse levels of free MC-LR in harvested porcine tissues, with Lemieux Oxidation employed to determine bound MC-LR in these tissues. MC-LR was not detected in the serum of treated animals from either experiment but free MC-LR was observed in the large intestine and kidney from two animals from the higher dosed group at levels of 1.4 and 1.9 µg/kg dry weight (dw) respectively. The results indicated 50% of higher dosed animals accumulated bound MC-LR in liver tissue, averaging 26.4 µg, approximately 1.1% of the dose administered. These results point to the potential uptake and accumulation of MC-LR in human liver tissue exposed chronically to sub-acute doses.


Assuntos
Toxinas Bacterianas/metabolismo , Mucosa Intestinal/metabolismo , Rim/metabolismo , Fígado/metabolismo , Microcistinas/metabolismo , Microcystis/fisiologia , Intoxicação por Água , Animais , Toxinas Bacterianas/química , Técnicas de Química Analítica , Ingestão de Líquidos , Exposição Ambiental/efeitos adversos , Indicadores Básicos de Saúde , Humanos , Toxinas Marinhas , Microcistinas/química , Modelos Animais , Suínos
10.
Anal Bioanal Chem ; 410(3): 801-825, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29273904

RESUMO

Liquid chromatography (LC) coupled with mass spectrometry (MS) is widely used for the determination of mycotoxins in cereals and cereal-based products. In addition to the regulated mycotoxins, for which official control is required, LC-MS is often used for the screening of a large range of mycotoxins and/or for the identification and characterization of novel metabolites. This review provides insight into the LC-MS methods used for the determination of co-occurring mycotoxins with special emphasis on multiple-analyte applications. The first part of the review is focused on targeted LC-MS approaches using cleanup methods such as solid-phase extraction and immunoaffinity chromatography, as well as on methods based on minimum cleanup (quick, easy, cheap, effective, rugged, and safe; QuEChERS) and dilute and shoot. The second part of the review deals with the untargeted determination of mycotoxins by LC coupled with high-resolution MS, which includes also metabolomics techniques to study the fate of mycotoxins in plants.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Grão Comestível/metabolismo , Grão Comestível/microbiologia , Metabolômica/métodos , Micotoxinas/metabolismo , Espectrometria de Massas em Tandem/métodos , Cromatografia de Afinidade/métodos , Grão Comestível/química , Análise de Alimentos/métodos , Fungos/isolamento & purificação , Fungos/metabolismo , Micotoxinas/análise , Extração em Fase Sólida/métodos
11.
Sci Rep ; 6: 36363, 2016 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-27821863

RESUMO

Controversy surrounds the proposed hypothesis that exposure to ß-methylamino-L-alanine (BMAA) could play a role in various neurodegenerative conditions including Alzheimer's disease (AD). Here we present the results of the most comprehensive scientific study on BMAA detection ever undertaken on brain samples from patients pathologically confirmed to have suffered from AD, and those from healthy volunteers. Following the full validation of a highly accurate and sensitive mass spectrometric method, no trace of BMAA was detected in the diseased brain or in the control specimens. This contradicts the findings of other reports and calls into question the significance of this compound in neurodegenerative disease. We have attempted to explain the potential causes of misidentification of BMAA in these studies.


Assuntos
Doença de Alzheimer/metabolismo , Diamino Aminoácidos/metabolismo , Encéfalo/metabolismo , Idoso , Idoso de 80 Anos ou mais , Toxinas de Cianobactérias , Feminino , Humanos , Masculino , Espectrometria de Massas
12.
J Agric Food Chem ; 63(38): 8574-83, 2015 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-26287989

RESUMO

A single-step lateral flow immunoassay was developed and validated to detect okadaic acid (OA) and dinophysis toxins (DTXs), which cause diarrhetic shellfish poisoning. The performance characteristics of the test were investigated, in comparison to reference methods (liquid chromatography tandem mass spectrometry and/or bioassay), using both spiked and naturally contaminated shellfish. A portable reader was used to generate a qualitative result, indicating the absence or presence of OA-group toxins, at concentrations relevant to the maximum permitted level (MPL). Sample homogenates could be screened in 20 min (including extraction and assay time) for the presence of free toxins (OA, DTX1, DTX2). DTX3 detection could be included with the addition of a hydrolysis procedure. No matrix effects were observed from the species evaluated (mussels, scallops, oysters, and clams). Results from naturally contaminated samples (n = 72) indicated no false compliant results and no false noncompliant results at <50% MPL. Thus, the development of a new low-cost but highly effective tool for monitoring a range of important phycotoxins has been demonstrated.


Assuntos
Bivalves/química , Imunoensaio/métodos , Toxinas Marinhas/análise , Ácido Okadáico/análise , Ostreidae/química , Pectinidae/química , Frutos do Mar/análise , Animais
13.
Biochem J ; 466(1): 55-68, 2015 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-25378054

RESUMO

Gremlin (Grem1) is a member of the DAN family of secreted bone morphogenetic protein (BMP) antagonists. Bone morphogenetic protein-7 (BMP-7) mediates protective effects during renal fibrosis associated with diabetes and other renal diseases. The pathogenic mechanism of Grem1 during diabetic nephropathy (DN) has been suggested to be binding and inhibition of BMP-7. However, the precise interactions between Grem1, BMP-7 and other BMPs have not been accurately defined. In the present study, we show the affinity of Grem1 for BMP-7 is lower than that of BMP-2 and BMP-4, using a combination of surface plasmon resonance and cell culture techniques. Using kidney proximal tubule cells and HEK (human embryonic kidney)-293 cell Smad1/5/8 phosphorylation and BMP-dependent gene expression as readouts, Grem1 consistently demonstrated a higher affinity for BMP-2>BMP-4>BMP-7. Cell-associated Grem1 did not inhibit BMP-2- or BMP-4-mediated signalling, suggesting that Grem1-BMP-2 binding occurred in solution, preventing BMP receptor activation. These data suggest that Grem1 preferentially binds to BMP-2 and this may be the dominant complex in a disease situation where levels of Grem1 and BMPs are elevated.


Assuntos
Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 4/metabolismo , Células Epiteliais/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Túbulos Renais Proximais/metabolismo , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 4/genética , Proteína Morfogenética Óssea 7/genética , Proteína Morfogenética Óssea 7/metabolismo , Linhagem Celular , Células Epiteliais/citologia , Regulação da Expressão Gênica , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Túbulos Renais Proximais/citologia , Fosforilação , Ligação Proteica , Transdução de Sinais , Proteína Smad1/genética , Proteína Smad1/metabolismo , Proteína Smad5/genética , Proteína Smad5/metabolismo , Proteína Smad8/genética , Proteína Smad8/metabolismo , Ressonância de Plasmônio de Superfície
14.
Talanta ; 122: 8-15, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24720955

RESUMO

A highly sensitive broad specificity monoclonal antibody was produced and characterised for microcystin detection through the development of a rapid surface plasmon resonance (SPR) optical biosensor based immunoassay. The antibody displayed the following cross-reactivity: MC-LR 100%; MC-RR 108%; MC-YR 68%; MC-LA 69%; MC-LW 71%; MC-LF 68%; and Nodularin 94%. Microcystin-LR was covalently attached to a CM5 chip and with the monoclonal antibody was employed in a competitive 4 min injection assay to detect total microcystins in water samples below the WHO recommended limit (1 µg/L). A 'total microcystin' level was determined by measuring free and intracellular concentrations in cyanobacterial culture samples as this toxin is an endotoxin. Glass bead beating was used to lyse the cells as a rapid extraction procedure. This method was validated according to European Commission Decision 96/23/EC criteria. The method was proven to measure intracellular microcystin levels, the main source of the toxin, which often goes undetected by other analytical procedures and is advantageous in that it can be used for the monitoring of blooms to provide an early warning of toxicity. It was shown to be repeatable and reproducible, with recoveries from spiked samples ranging from 74 to 123%, and had % CVs below 10% for intra-assay analysis and 15% for inter-assay analysis. The detection capability of the assay was calculated as 0.5 ng/mL for extracellular toxins and 0.05 ng/mL for intracellular microcystins. A comparison of the SPR method with LC-MS/MS was achieved by testing six Microcystis aeruginosa cultures and this study yielded a correlation R(2) value of 0.9989.


Assuntos
Anticorpos Monoclonais/metabolismo , Cianobactérias/metabolismo , Líquido Intracelular/metabolismo , Microcistinas/metabolismo , Peptídeos Cíclicos/metabolismo , Ressonância de Plasmônio de Superfície/métodos , Animais , Cianobactérias/química , Líquido Intracelular/química , Líquido Intracelular/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Microcistinas/análise , Microcystis/química , Microcystis/metabolismo , Peptídeos Cíclicos/análise , Reprodutibilidade dos Testes , Ressonância de Plasmônio de Superfície/normas
15.
Biomarkers ; 18(8): 639-49, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24102089

RESUMO

CONTEXT: Freshwater cyanobacterial toxins, microcystins, may be a contributing factor to the development of hepatocellular cancer and colorectal cancer. OBJECTIVES: This review summarizes the toxicity data, exposure routes and the methodologies available to determine exposure to elucidate the relationship to liver and colorectal cancer. METHODS: Literature searches were conducted using Medline, PubMed and Web of Science. RESULTS: There is evidence of human poisonings resulting from exposure to microcystins, however current methods rely on targeted approaches only suitable for acute exposure. No methods exist for the determination of chronic exposure to microcystins. CONCLUSIONS: With the growing evidence of exposure to microcystins and the possible links to cancer, methods to measure medium to long-term human exposure are needed. The identification and validation of candidate biomarkers are key to undertaking urgently required epidemiological studies.


Assuntos
Exposição Ambiental , Microcistinas/análise , Microcistinas/toxicidade , Testes de Carcinogenicidade , Humanos , Microcistinas/farmacocinética , Testes de Mutagenicidade
16.
Talanta ; 116: 663-9, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24148459

RESUMO

A lateral flow immunoassay (LFIA) has been developed and fully validated to detect the primary amnesic shellfish poisoning (ASP) toxin, domoic acid (DA). The performance characteristics of two versions of the test were investigated using spiked and naturally contaminated shellfish (mussels, scallops, oysters, clams, and cockles). The tests provide a qualitative result, to indicate the absence or presence of DA in extracts of shellfish tissues, at concentrations that are relevant to regulatory limits. The new rapid assay (LFIA version 2) was designed to overcome the performance limitations identified in the first version of the assay. The improved test uses an electronic reader to remove the subjective nature of the generated results, and the positive cut-off for screening of DA in shellfish was increased from 10 ppm (version 1) to 17.5 ppm (version 2). A simple extraction and test procedure was employed, which required minimal equipment and materials; results were available 15 min after sample preparation. Stability of the aqueous extracts at room temperature (22 °C) at four time points (up to 245 min after extraction) and across a range of DA concentrations was 100.3±1.3% and 98.8±2.4% for pre- and post-buffered extracts, respectively. The assay can be used both within laboratory settings and in remote locations. The accuracy of the new assay, to indicate negative results at or below 10 ppm DA, and positive results at or above 17.5 ppm, was 99.5% (n=216 tests). Validation data were obtained from a 2-day, randomised, blind study consisting of multiple LFIA lots (n=3), readers (n=3) and operators (n=3), carrying out multiple extractions of mussel tissue (n=3) at each concentration (0, 10, 17.5, and 20 ppm). No matrix effects were observed on the performance of the assay with different species (mussels, scallops, oysters, clams, and cockles). There was no impact on accuracy or interference from other phycotoxins, glutamic acid or glutamine with various strip incubations (8, 10, and 12 min). The accuracy of the assay, using naturally contaminated samples to indicate negative results at or below 12.5 ppm and positive results at or above 17.5 ppm, was 100%. Variability between three LFIA lots across a range of DA concentrations, expressed as coefficient of variation (% CV), was 1.1±0.4% (n=2 days) based on quantitative readings from the electronic reader. During an 8 week stability study, accuracy of the method with test strips stored at various temperatures (6, 22, 37 and 50 °C) was 100%. Validation for both versions included comparisons with results obtained using reference LC-UV methods.


Assuntos
Imunoensaio , Ácido Caínico/análogos & derivados , Toxinas Marinhas/isolamento & purificação , Moluscos/química , Frutos do Mar/análise , Animais , Ensaios de Triagem em Larga Escala , Ácido Caínico/isolamento & purificação , Reologia , Sensibilidade e Especificidade
17.
Anal Chim Acta ; 769: 108-13, 2013 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-23498128

RESUMO

The study details the development of a fully validated, rapid and portable sensor based method for the on-site analysis of microcystins in freshwater samples. The process employs a novel lysis method for the mechanical lysis of cyanobacterial cells, with glass beads and a handheld frother in only 10 min. The assay utilises an innovative planar waveguide device that, via an evanescent wave excites fluorescent probes, for amplification of signal in a competitive immunoassay, using an anti-microcystin monoclonal with cross-reactivity against the most common, and toxic variants. Validation of the assay showed the limit of detection (LOD) to be 0.78 ng mL(-1) and the CCß to be 1 ng mL(-1). Robustness of the assay was demonstrated by intra- and inter-assay testing. Intra-assay analysis had % C.V.s between 8 and 26% and recoveries between 73 and 101%, with inter-assay analysis demonstrating % C.V.s between 5 and 14% and recoveries between 78 and 91%. Comparison with LC-MS/MS showed a high correlation (R(2)=0.9954) between the calculated concentrations of 5 different Microcystis aeruginosa cultures for total microcystin content. Total microcystin content was ascertained by the individual measurement of free and cell-bound microcystins. Free microcystins can be measured to 1 ng mL(-1), and with a 10-fold concentration step in the intracellular microcystin protocol (which brings the sample within the range of the calibration curve), intracellular pools may be determined to 0.1 ng mL(-1). This allows the determination of microcystins at and below the World Health Organisation (WHO) guideline value of 1 µg L(-1). This sensor represents a major advancement in portable analysis capabilities and has the potential for numerous other applications.


Assuntos
Cianobactérias/metabolismo , Água Doce/análise , Imunoensaio , Microcistinas/análise , Anticorpos Monoclonais/imunologia , Cromatografia Líquida de Alta Pressão , Microcistinas/imunologia , Microcystis/crescimento & desenvolvimento , Microcystis/metabolismo , Espectrometria de Massas em Tandem
18.
Biosens Bioelectron ; 41: 691-7, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23102433

RESUMO

Marine dinoflagellates of the genera Alexandrium are well known producers of the potent neurotoxic paralytic shellfish toxins that can enter the food web and ultimately present a serious risk to public health in addition to causing huge economic losses. Direct coastal monitoring of Alexandrium spp. can provide early warning of potential shellfish contamination and risks to consumers and so a rapid, sensitive, portable and easy-to-use assay has been developed for this purpose using an innovative planar waveguide device. The disposable planar waveguide is comprised of a transparent substrate onto which an array of toxin-protein conjugates is deposited, assembled in a cartridge allowing the introduction of sample, and detection reagents. The competitive assay format uses a high affinity antibody to paralytic shellfish toxins with a detection signal generated via a fluorescently labelled secondary antibody. The waveguide cartridge is analysed by a simple reader device and results are displayed on a laptop computer. Assay speed has been optimised to enable measurement within 15 min. A rapid, portable sample preparation technique was developed for Alexandrium spp. in seawater to ensure analysis was completed within a short period of time. The assay was validated and the LOD and CCß were determined as 12 pg/mL and 20 pg/mL respectively with an intra-assay CV of 11.3% at the CCß and an average recovery of 106%. The highly innovative assay was proven to accurately detect toxin presence in algae sampled from the US and European waters at an unprecedented cell density of 10 cells/L.


Assuntos
Técnicas Biossensoriais/instrumentação , Monitoramento Ambiental/instrumentação , Eucariotos/química , Toxinas Marinhas/análise , Frutos do Mar/análise , Espectrometria de Fluorescência/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Desenho de Equipamento , Análise de Falha de Equipamento , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Talanta ; 81(1-2): 630-6, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20188974

RESUMO

A rapid surface plasmon resonance (SPR) screening assay has been developed for the combined detection of T-2 and HT-2 toxins in naturally contaminated cereals using a sensor chip coated with an HT-2 toxin derivative and a monoclonal antibody. The antibody raised against HT-2 displayed high cross-reactivity with T-2 toxin while there was no cross-reaction observed with other commonly occurring trichothecenes. A simple extraction procedure using 40% methanol was applied to baby food, breakfast cereal, and wheat samples prior to biosensor analysis. Limits of detection (LOD) for each matrix were determined as 25 microg kg(-1) for baby food and breakfast cereal and 26 microg kg(-1) for wheat. Intra-assay precision (n=6) was calculated for each matrix. The results were expressed as the relative standard deviation and determined as 2.8% (100 microg kg(-1)) and 1.8% (200 microg kg(-1)) in breakfast cereal, 4.6% (50 microg kg(-1)) and 3.6% (100 microg kg(-1)) in wheat and 0.97% (25 microg kg(-1)) and 6.3% (50 microg kg(-1)) in baby food. Between run precision (n=3) performed at the same levels yielded relative standard deviations of 6.7% and 3.9% for breakfast cereals, 3.3% and 1.6% for wheat and 6.8% and 0.08% for baby food, respectively.


Assuntos
Grão Comestível/química , Imunoensaio/métodos , Alimentos Infantis/análise , Fenômenos Ópticos , Toxina T-2/análogos & derivados , Toxina T-2/análise , Zea mays/química , Análise de Alimentos , Reprodutibilidade dos Testes , Toxina T-2/imunologia , Fatores de Tempo
20.
J Agric Food Chem ; 58(16): 8936-41, 2010 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-23654230

RESUMO

A rapid screening assay (9 min/sample) has been developed and validated for the detection of deoxynivalenol in durum wheat, wheat products, and maize-based baby foods using an SPR biosensor. Through a single laboratory validation, the limits of detection (LOD) for wheat, wheat-based breakfast cereal, and maize-based baby food were 57, 9, and 6 µg/kg, respectively. Intra-assay and interassay precisions were calculated for each matrix at the maximum and half-maximum European Union regulatory limits and expressed as the coefficient of variation (CV). All CVs fell below 10% with the exception of the between-run CV for breakfast cereal. Recoveries at the concentrations tested ranged from 92 to 115% for all matrices. Action limits of 161, 348, and 1378 µg/kg were calculated for baby food, wheat-based breakfast cereal, and wheat, respectively, and the linear range of the assay was determined as 250-2000 µg/kg.


Assuntos
Imunoensaio/métodos , Alimentos Infantis/análise , Ressonância de Plasmônio de Superfície/métodos , Tricotecenos/análise , Triticum/química , Zea mays/química , Animais , Contaminação de Alimentos/análise , Camundongos , Camundongos Endogâmicos BALB C
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...