By Dr. Frederik Wuppermann and Dr. Uwe Aulwurm
Ergot alkaloids are mycotoxins produced by fungi (Claviceps sp.) on various grain species with a highly toxic impact on the health of consumers (Figure 1). The toxins provoke symptoms summarized as ergotism.
The toxins are characterized by two different isomers, which occur under different pH conditions, they are named –ines and –inines. The main toxins found are ergocristine, -inine, ergometrine, -inine, ergosine, -inine, ergocryptine, -inine, ergotamine, -inine, ergocornine, -inine. The assessment of toxin amount becomes necessary due to the toxic effects of ergot alkaloids. For this purpose an ELISA was developed to detect all ergot alkaloids in various crop material and the detected amounts of ergot alkaloids were correlated with LC-MS data.
The sample is extracted by 40/60 methanol / 0.25% phosphoric acid as described by Ware et al. 2000. After centrifugation the sample was diluted with sample dilution buffer and filtered again. The filtered sample was applied in the ELISA plate and compared with a standard solution (enclosed in the ErgoREAD kit). The enzyme immune reaction is performed as depicted in Figure 2.
Analysis of wheat samples:
Analysis of Rye Samples:
Comparative Analysis of Naturally Contaminated Samples:
The samples showed good correlation between 0 to 10 ppm, indicating that the ELISA is suitable for the screening of various crop material for the presence of ergot alkaloids. The partially over quantification in the comparative analysis could be due to the cross reactivity of the ELISA against various ergot alkaloids which were not monitored by the LC-MS or HPLC analysis.
The ELISA shows significant cross reactivity against various ergot alkaloids e.g. ergonovin (ergometrine or ergocristine) and can be used to determine the qualitative stuatus of a crop sample concernig the sum of ergot alkaloids.
The ErgoREAD ELISA is an appropriate tool for screening wheat, rye and triticale samples for presence of ergot alkaloids. The range of measurement is from 0 to 5 ppm. Due to the readout as the sum of all reactive ergot alkaloids, the cutoff for critical samples is 0.4 ppm. All shown ELISA samples are correlated with HPLC. The total amount of samples which need to undergo LC-MS analysis could be dramatically reduced.
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