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- 2,4-Dinitrophenylhydrazine (2)
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- Deacetyl tenuazonic acid (2)
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Eingeladener Vortrag
- nein (7)
Aims: A laboratory study was conducted to evaluate the influence of cocultivation of toxigenic Fusarium (F.) and Alternaria (A.) fungi with respect to growth and mycotoxin production.
Methods and Results: Fusarium culmorum Fc13, Fusarium graminearum Fg23 and two Alternaria tenuissima isolates (At18 and At220) were simultaneously or consecutively co-incubated on wheat kernels in an in vitro test system. Fungal biomass was quantified by determining ergosterol content. Three Fusarium toxins (DON, NIV and ZON) and three Alternaria toxins (AOH, AME and ALT) were analysed by a newly developed HPLC/MS/MS method. In simultaneous cocultures, the fungal biomass was enhanced up to 460% compared with individual cultures; Alternaria toxins were considerably depressed down to <5%. Combining At18 and At220 with Fg23 inhibited the toxin production of both fungal partners. In contrast, Fc13 increased its DON and ZON production in competitive interaction with both A. strains.
Conclusions: The interfungal competitive effects aid the understanding of the processes of competition of both fungi in natural environments and the involvement of mycotoxins as antifungal factors.
Significance and Impact of Study:
Cocultivation significantly affects fungal growth and mycotoxin production of phytopathogenic Alternaria and Fusarium strains. The impact of mycotoxins on the interfungal competition is highlighted.
Deacetyl tenuazonic acid
(2009)
Tenuazonic acid (TA) is a major Alternaria mycotoxin. In the present work a novel approach for the detection of TA in cereals by liquid chromatographyion-trap multistage mass spectrometry after derivatization with 2,4-dinitrophenylhydrazine is described. The product of the derivatization reaction and its major MS2 fragments were characterised by Fourier transform-ion cyclotron resonance tandem mass spectrometry. Without preconcentration, the established method features a limit of detection of 10 µg/kg using 2 g of sample in a rapid workup procedure. Accuracy, precision and linearity were evaluated in the working range of 505000 µg/kg. TA was detected in 13 and quantified in 3 out of 27 cereal samples obtained from a local supermarket, the average content being 49 µg/kg (highest incidence: 851 ± 41 µg/kg).
Certified reference materials (CRMs) are a versatile tool for quality assurance in the chemical laboratory. In the case of acrylamide analysis, the availability of appropriate materials was rather limited. This lack of acrylamide matrix CRMs has now been overcome by the development of two European reference materials (ERM) for the determination of acrylamide in food (crispbread, ERM-BD272, and rusk, ERM-BD274). This article describes the preparation of the materials, provides the results of the homogeneity and stability studies, and presents and discusses the outcome of the certification studies. Expert laboratories from different European countries took part in the certification studies using various analytical methods. The acrylamide mass fractions were certified to 980 µg kg-1 for crispbread and 74 µg kg-1 for rusk.