Search results for "toxin"
showing 10 items of 1434 documents
Extraction and analysis of ochratoxin A in bread using pressurised liquid extraction and liquid chromatography.
2005
A pressurised liquid extraction (PLE) method for the analysis of ochratoxin A (OTA) in bread samples is given. Parameters such as solvent, temperature, pressure and time were investigated thoroughly. The optimized PLE conditions were: methanol as extraction solvent, 80 degrees C, 2000 psi and a 5-min cycle. OTA was determined by liquid chromatography coupled with fluorescence detection and confirmed by methyl ester derivatization. Under these conditions OTA recovery is 92.3% with a RSD of 5%. Limits of detection and quantification were 0.02 and 0.06 microg/kg, respectively. The proposed method was applied to 20 bread samples, finding two positive samples with OTA levels below the maximum pe…
Determination of ochratoxin A in maize bread samples by LC with fluorescence detection.
2007
Ochratoxin A (OTA) is a secondary fungal metabolite produced by several moulds, mainly by Aspergillus ochraceus, A. carbonarius, A. niger and by Penicillium verrucosum. The present work shows the results of comparative studies using different procedures for the analysis of OTA in maize bread samples. The studied analytical methods involved extraction with different volumes of PBS/methanol, different extraction apparatus, and clean-up through immunoaffinity columns. The separation and identification were carried out by high-performance liquid chromatography with fluorescence detection. The optimized method for analysis of OTA in maize bread involved extraction with PBS:methanol (50:50), and …
Multimycotoxin LC-MS/MS Analysis in Tea Beverages after Dispersive Liquid-Liquid Microextraction (DLLME).
2017
The aim of the present study was to develop a multimycotoxin liquid chromatography tandem mass spectrometry (LC-MS/MS) method with a dispersive liquid-liquid microextraction procedure (DLLME) for the analysis of AFs, 3aDON, 15aDON, NIV, HT-2, T-2, ZEA, OTA, ENNs, and BEA in tea beverages and to evaluate their mycotoxin contents. The proposed method was characterized in terms of linearity, limits of detection (LODs), limits of quantification (LOQs), recoveries, repeatability (intraday precision), reproducibility (interday precision), and matrix effects to check suitability. The results show LODs in the range of 0.05-10 μg/L, LOQs in the range of 0.2-33 μg/L, and recoveries in the range of 65…
Determination of type A and type B trichothecenes in paprika and chili pepper using LC-triple quadrupole-MS and GC-ECD.
2011
There is a need to develop sensitive and accurate analytical methods for determining deoxynivalenol (DON), HT-2 toxin and T-2 toxin in paprika to properly assess the relevant risk of human exposure. An optimized analytical method for determination of HT-2 toxin and T-2 toxin using capillary gas chromatography with electron capture detection and another method for determination of DON by liquid chromatography-mass spectrometry in paprika was developed. The method for determination of HT-2 toxin and T-2 toxin that gave the best recoveries involved extraction of the sample with acetonitrile-water (84:16, v/v), clean-up by solid-phase extraction on a cartridge made of different sorbent material…
Role of Bacillus thuringiensis Toxin Domains in Toxicity and Receptor Binding in the Diamondback Moth
1999
ABSTRACT The toxic fragment of Bacillus thuringiensis crystal proteins consists of three distinct structural domains. There is evidence that domain I is involved in pore formation and that domain II is involved in receptor binding and specificity. It has been found that, in some cases, domain III is also important in determining specificity. Furthermore, involvement of domain III in binding has also been reported recently. To investigate the role of toxin domains in the diamondback moth ( Plutella xylostella ), we used hybrid toxins with domain III substitutions among Cry1C, Cry1E, and Cry1Ab. Neither Cry1E nor G27 (a hybrid with domains I and II from Cry1E and domain III from Cry1C) was to…
Congenital secretory diarrhoea caused by activating germline mutations in GUCY2C
2016
Objective Congenital sodium diarrhoea (CSD) refers to a form of secretory diarrhoea with intrauterine onset and high faecal losses of sodium without congenital malformations. The molecular basis for CSD remains unknown. We clinically characterised a cohort of infants with CSD and set out to identify disease-causing mutations by genome-wide genetic testing. Design We performed whole-exome sequencing and chromosomal microarray analyses in 4 unrelated patients, followed by confirmatory Sanger sequencing of the likely disease-causing mutations in patients and in their family members, followed by functional studies. Results We identified novel de novo missense mutations in GUCY2C, the gene encod…
Clostridium difficile heterogeneously impacts intestinal community architecture but drives stable metabolome responses
2015
Clostridium difficile-associated diarrhoea (CDAD) is caused by C. difficile toxins A and B and represents a serious emerging health problem. Yet, its progression and functional consequences are unclear. We hypothesised that C. difficile can drive major measurable metabolic changes in the gut microbiota and that a relationship with the production or absence of toxins may be established. We tested this hypothesis by performing metabolic profiling on the gut microbiota of patients with C. difficile that produced (n=6) or did not produce (n=4) toxins and on non-colonised control patients (n=6), all of whom were experiencing diarrhoea. We report a statistically significant separation (P-value o0…
Toxin production by Campylobacter spp
1997
Of all the virulence factors that were proposed for Campylobacter jejuni and related species to cause disease in humans, the discovery of toxin production was the most promising but led to a rather confusing and even disappointing stream of data. The discussion of whether proteinaceous exotoxins are relevant in disease remains open. One important reason for this lack of consensus is the anecdotal nature of the literature reports. To provide a basis for an unbiased opinion, this review compiles all described exotoxins, compares their reported properties, and provides a summary of animal model studies and clinical data. The toxins are divided into enterotoxins and cytotoxins and are sorted ac…
Expression and purification of polyhistidine-tagged rotavirus NSP4 proteins in insect cells
2003
The rotavirus nonstructural NSP4 protein, a transmembrane endoplasmic reticulum-specific glycoprotein, has been described as the first viral enterotoxin. Purified NSP4 or a peptide corresponding to NSP4 residues 114-135 induces diarrhea in young mice. NSP4 has a membrane-destabilizing activity and causes an increase in intracellular calcium levels and chloride secretion by a calcium-dependent signalling pathway in eucaryotic cells. In this study, four recombinant baculoviruses were generated expressing the rotavirus NSP4 glycoprotein from the human strains Wa and Ito, the porcine strain OSU, and the simian strain SA11, which belong to two different NSP4 genotypes, A and B. The recombinant g…
Identification of a novel VP4 genotype carried by a serotype G5 porcine rotavirus strain
2006
AbstractRotavirus genome segment 4, encoding the spike outer capsid VP4 protein, of a porcine rotavirus (PoRV) strain, 134/04-15, identified in Italy was sequenced, and the predicted amino acid (aa) sequence was compared to those of all known VP4 (P) genotypes. The aa sequence of the full-length VP4 protein of the PoRV strain 134/04-15 showed aa identity values ranging from 59.7% (bovine strain KK3, P8[11]) to 86.09% (porcine strain A46, P[13]) with those of the remaining 25 P genotypes. Moreover, aa sequence analysis of the corresponding VP8* trypsin cleavage fragment revealed that the PoRV strain 134/04-15 shared low identity, ranging from 37.52% (bovine strain 993/83, P[17]) to 73.6% (po…