Abstract
The mutagenic patterns of A. flavus, A. parasiticus and A. fumigatus extracts were evaluated. These strains of toxigenic Aspergillus were collected from the agricultural environment. The Ames test was performed on Salmonella typhimurium strains TA98, TA100 and TA102, without and with S9mix (exogenous metabolic activation system). These data were compared with the mutagenicity of the corresponding pure mycotoxins tested alone or in reconstituted mixtures with equivalent concentrations, in order to investigate the potential interactions between these molecules and/or other natural metabolites. At least 3 mechanisms are involved in the mutagenic response of these aflatoxins: firstly, the formation of AFB1-8,9-epoxide upon addition of S9mix, secondly the likely formation of oxidative damage as indicated by significant responses in TA102, and thirdly, a direct mutagenicity observed for higher doses of some extracts or associated mycotoxins, which does not therefore involve exogenously activated intermediates. Besides the identified mycotoxins (AFB1, AFB2 and AFM1), additional “natural” compounds contribute to the global mutagenicity of the extracts. On the other hand, AFB2 and AFM1 modulate negatively the mutagenicity of AFB1 when mixed in binary or tertiary mixtures. Thus, the evaluation of the mutagenicity of “natural” mixtures is an integrated parameter that better reflects the potential impact of exposure to toxigenic Aspergilli.
Highlights
We have previously demonstrated in an agricultural environment (Normandy, France), that oilseed cakes and maize silage used for cattle food could be contaminated with Aspergilli, especially A. flavus, A. parasiticus and A. fumigatus, even in temperate/mild climate [1,2]
The two strains of A. fumigatus were toxigenic, producing roughly comparable fumagillin and verruculogen levels, but they differ with regard to their gliotoxin synthesis potential (Table 1)
Besides identified mycotoxins, additional secondary metabolites should contribute to the global mutagenic responses evaluated with the Ames test
Summary
We have previously demonstrated in an agricultural environment (Normandy, France), that oilseed cakes and maize silage used for cattle food could be contaminated with Aspergilli, especially A. flavus, A. parasiticus and A. fumigatus, even in temperate/mild climate [1,2]. Some species belonging to Aspergillus genus are well-known as potential producers of various mycotoxins such as aflatoxins, gliotoxin, verruculogen or fumagillin. The toxic effects of these purified mycotoxins. Aflatoxin B1 (AFB1 ), produced by the Aspergilli flavus group, had well known mutagenic and genotoxic properties and is classified in group 1 by the International Agency for Research on Cancer (IARC), due to its carcinogenic potential [10]. Gliotoxin, produced by A. fumigatus, was found to be genotoxic using the bacterial repair assay
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
