A novel biosensor for the detection of zearalenone family mycotoxins in milk.
ABSTRACT In this study, a method for detecting estrogenic mycotoxin residues in milk was developed utilizing bioluminescent whole-cell biosensors. Milk products of various compositions were spiked with the estrogenic mycotoxins zearalenone and its metabolites zearalanone, alpha-zearalanol, beta-zearalanol, alpha-zearalenol and beta-zearalenol. The estrogenic response was detected by a whole-cell biosensor based on a genetically modified Saccharomyces cerevisiae strain that in the presence of an estrogenic compound produces firefly luciferase-enzyme and further light emission within a system provided with D-luciferin substrate. The results show that the yeast sensor reacts to mycotoxins with typical sigmoidal response at nanomolar concentrations. The response differs in different milk products with regard to the fat content of the milk. Due to short assay time of less than 3h and automation the approach can be used as a bioavailability and activity screening method prior to more detailed chemical analysis.
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ABSTRACT: The most frequent toxigenic fungi in Europe are Aspergillus, Penicillium and Fusarium species. They produce aflatoxin B1 transformed into aflatoxin M1 found in the milk, as well as Ochratoxins and Zearalenone, Fumonisin B1, T-2 toxin, HT-2 toxin and deoxynivalenol (vomitoxin), which are of increasing concern in human health. These mycotoxins are under continuous survey in Europe, but the regulatory aspects still need to be set up and/or harmonised at European level. They are found in foodstuffs and are not destroyed by normal industrial processing or cooking since they are heat-stable. Some of their metabolites are still toxic and may be involved in human diseases. Their toxic effects (liver, kidney and hematopoetic toxicity, immune toxicity, reproduction toxicity, foetal toxicity and teratogenicity, and mainly carcinogenicity) are mostly known in experimental models, the extrapolation to humans being always inaccurate. The inaccuracy of extrapolation to humans may be explained by the lack of adequate food consumption data, lack of knowledge about relative health risks associated with specifically proposed limits and by the possibility of synergism with other mycotoxins present in the same food commodities. Other pathological causes are viral hepatitis, immune or hormonal deficiencies or organ dysfunction. Even when a specific biomarker of a given mycotoxin is identified in humans, it remains difficult to establish the relation with a given illness, because of genetic polymorphism and the possible beneficial influence of diet, and because other environmental toxicants may well interfere. The acceptable daily intake limits are mostly based on animal data and may be too high, due to the differences in the sensitivity of different animal species. The prevention involves first reduction of mycotoxin levels in foodstuffs and further increasing the intake of diet components such as vitamins, antioxidants and substances known to prevent carcinogenesis.Toxicology Letters 03/2002; 127(1-3):19-28. · 3.15 Impact Factor
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ABSTRACT: Controversy has arisen concerning the likelihood of adverse health effects due to exposure to hormonally active agents or endocrine modulators such as environmental estrogens. With the aim to improve the basis for their toxicological evaluation, several chemicals of anthropogenic (bisphenol A, octylphenol, o,p'-DDT) and of natural origin (daidzein, genistein) were investigated with regard to their mode of hormonal action and potency as well as toxicokinetics. Experimental toxicodynamic and toxicokinetic data illustrate important points in a comparative assessment of environmental estrogens. A novel concept, the Hygiene-Based Margine of Safety (HBMOS), has been suggested to characterize the relative impact of these potential endocrine modulators on human health: It integrates exposure scenarios (i.a. those generated within the European Existing Chemicals Programme) and in vivo rodent potency data for xenoestrogens and for dietary phytoestrogens. On the basis of these informations, HBMOS values calculated for the alkylphenol and bisphenol A appear sufficiently high to ensure the absence of a practical risk to human health under the present exposure conditions. For slowly accumulating compounds (e.g. DDT) with much longer half-lifes than isoflavones, such comparison should be based on comparative blood levels rather than on scenarios of daily exposures.Toxicology Letters 03/2002; 127(1-3):225-37. · 3.15 Impact Factor
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ABSTRACT: A microarray, which covers most of the known relevant mycotoxin biosynthesis genes, has been developed. The microarray carries oligonucleotides of the fumonisin, the aflatoxin, the ochratoxin, the trichothecene (type A and B) and the patulin biosynthesis pathways. For trichothecene producing Fusaria the biosynthesis cluster of trichothecene producing Fusarium sporotrichioides (type A) and of Gibberrella zeae (type B, teleomorph of F. graminearum) have been spotted. The aflatoxin cluster carries oligonucleotides specific for Aspergillus flavus. The ochratoxin pattern is specific for ochratoxin A producing Penicillia, the fumonisin cluster is specific for G. moniliformis (teleomorph of F. verticillioides) and the patulin genes have been obtained from Penicillium expansum. The microarray is designed in a way that newly identified pathway genes can be added easily at any time. The microarray was used to detect the activation of all gene clusters under conditions conducive for mycotoxin biosynthesis. According to the results the obtained signals were specific under the hybridization conditions used and only insignificant cross-hybridizations occurred. The microarray was used to demonstrate differences in mycotoxin pathway gene expressions after growth on various media for trichothecene and ochratoxin A biosynthesis. It was used further to study and compare the expression kinetics of the trichothecene biosynthesis genes of Fusarium on different trichothecene supporting media. An expression pattern indicative for trichothecene biosynthesis could be identified.International Journal of Food Microbiology 07/2007; 117(2):131-40. · 3.43 Impact Factor