Molecular and life-history effects of a natural toxin on herbivorous and non-target soil arthropods

Natural toxins, such as isothiocyanate (ITC), are harmful secondary metabolites produced by plants. Many natural toxins occur in commercial crops, yet their possible negative repercussions on especially non-target soil organisms are largely unknown. This study examined life-history and gene transcriptional responses to 2-phenylethyl ITC on two soil arthropod species: Folsomia candida and Protaphorura fimata. To that end the standardized ISO guideline for ecotoxicological tests and a microarray for F. candida were used. The dissipation of 2-phenylethyl ITC in natural soil was investigated using GC-MS/MS for quantification. Half-lives, tested at four concentration levels in natural soil, were on average 16 h with biodegradation as the plausible main removal process. Regardless, toxic effects on reproduction were shown for F. candida and P. fimata, with EC50 values of around 11.5 nmol/g soil illustrating the toxic character of this compound. Gene expression profiles revealed the importance of fatty acid metabolism at low exposure concentrations (EC10), which is associated with the lipophilic nature of 2-phenylethyl ITC. At higher concentrations (EC50) gene expression became more ubiquitous with over-expression of especially stress-related genes and sugar metabolism. The regulation of a gene encoding a precursor of follistatin, furthermore, implied the inhibition of reproduction and may be an important molecular target that can be linked to the observed adverse effect of life-history traits

Differential Detection of Potentially Hazardous Fusarium Species in Wheat Grains by an Electronic Nose

Fungal infestation on wheat is an increasingly grave nutritional problem in many countries worldwide. Fusarium species are especially harmful pathogens due to their toxic metabolites. In this work we studied volatile compounds released by F. cerealis, F. graminearum, F. culmorum and F. redolens using SPME-GC/MS. By using an electronic nose we were able to differentiate between infected and non-infected wheat grains in the post-harvest chain. Our electronic nose was capable of distinguishing between four wheat Fusaria species with an accuracy higher than 80%

Report of 104th annual meeting of the Association of Official Analytical Chemists (AOAC) at New Orleans, U.S.A., 10-13 September 1990

Abstract niet beschikbaarIn this report summaries are presented of lectures, discussions and poster presentations of the 104th AOAC Annual International Meeting, New Orleans, U.S.A., 10-13 September 1990. Emphasis is laid on new developments, studyresults, facts and opinions in the area of mycotoxin research. Some important conclusions: - Microbial infections through food are worldwide significantly increasing. - There is a growing interest for (certified) reference materials for organic analytes. - The number of commercial ELISA testkits for mycotoxins and veterinary drugs is rapidly growing. They are applied in practice, but the time-consuming AOAC-validation procedures cannot keep up with the developments. The first immunoaffinity/HPLC analysis procedure for aflatoxins B1, B2, G1, G2 probably will be approved by AOAC for official first action status. - Combinations of TLC/HPLC and ELISA offer new perspectives for selective determination of mycotoxins and metabolites at low levels of detection. - Fumonisin, a recently discovered Fusarium mycotoxin, leads to much concern among scientists and administrators, because of its assumed relation with human oesophageal cancer and its proven relationshcip with a deathly horse- disease in the U.S.A. - As yet, it is unclear whether problems may be expected with aflatoxin contamination in maize in the U.S.A. this year. In certain areas, the harvest is delayed because of drought. There are signs, that this year's peanut harvest in Southern U.S.A. States is hit hard by drought and aflatoxin contamination.RIV