AVALIAÇÃO DA INCIDÊNCIA DE FUNGOS FILAMENTOSOS E DE MICOTOXINAS EM MILHO NACIONAL

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Publications

Three new aflatoxigenic species of Aspergillus section Flavi isolated in Portugal

Publication . Soares, Célia; Peterson, Stephen W.; Rodrigues, Paula; Lima, Nelson; Venâncio, Armando

Three new aflatoxin-producing species isolated from two Portuguese commodities, almonds and maize, are described. A polyphasic approach based on phenotypic (morphology and extrolites) and molecular characterizations was used to identify these isolates as belonging to new species. From the study of the twenty two isolates obtained in maize and almonds, two were identified as Aspergillus flavus, six as A. minisclerotigenes and four as A. parasiticus. Examination of morphological characters combined with the analyses of aflatoxins and CPA production and molecular data revealed that ten of the Aspergillus section Flavi strains that were isolated do not match that of described species of the section. The multilocus analyses were performed using different primers for DNA regions. Molecular characterization showed that A. mottae, A. sergii and A. transmontanensis are well supported by phylogenetic analyses of the combined data. Aspergillus transmontanensis and A. sergii are phylogenetically related to A. parasiticus. Aspergillus mottae is phylogenetically ancestral to A. flavus and A. parasiticus. Therefore three new species are proposed Aspergillus mottae, Aspergillus sergii and Aspergillus transmontanensis.

2011Conference object

Open access

Three new species of Aspergillus section Flavi isolated from almonds and maize in Portugal

Publication . Soares, Célia; Rodrigues, Paula; Peterson, Stephen W.; Lima, Nelson; Venâncio, Armando

Three new aflatoxin-producing species belonging to Aspergillus section Flavi are described, Aspergillus mottae, Aspergillus sergii and Aspergillus transmontanensis. These species were isolated from two Portuguese commodities, almonds and maize. A polyphasic approach based on phenotypic (morphology and extrolites) and molecular characterizations was used to identify these isolates as belonging to new species. Molecular characterization showed that A. transmontanensis and A. sergii are phylogenetically related to Aspergillus parasiticus whereas A. mottae is phylogenetically ancestral to Aspergillus flavus and A. parasiticus.

2012Journal article

Open access

Rapid HPLC method for simultaneous detection of aflatoxins and cyclopiazonic from Aspergillus section Flavi

Publication . Soares, Célia; Rodrigues, Paula; Freitas-Silva, Otniel; Abrunhosa, Luís; Venâncio, Armando

Mycotoxins are secondary metabolites produced by moulds and are an important world-wide food safety concern. Among the most relevant mycotoxigenic producer fungi are some Aspergillus species in particular those belonging to the Aspergillus section Flavi. These are known to produce the highly carcinogenic aflatoxins in agricultural commodities. Due to its impact in animal and human health, these species are among the most intenSively studied ones, being well known producers of aflatoxins (AFB1 , AFB2; AFG1 and AFG2) and cyciopiazonic acid (CPA). Aflatoxins are mainly produced by some strains of Aspergillus flavus and Aspergillus nomius and by most, if not all, strains of Aspergillus parasiticus. On the other hand, cyclopiazonic acid, which naturally occurs in a large variety of crop products as a co-contaminant with aflatoxins, is mainly produced by Aspergillus flavus strains. Together they have been shown to cause health problems in animals and humans, resulting in important economic losses. The production of CPA by Aspergillus section Flavi may also be routinely used for identification purposes since A. parasiticus, A. flavus and A. nomius, exhibit different mycotoxin profiles. The detection and quantification of both these mycotoxins is usually done separately by HPLC with UV detection for CPA and fluorescence detection after post-column derivatization for aflatoxins. There isn't a chromatographic method available to detect simultaneously CPA and the main four aflatoxins.

2010Conference object

Metadata only

Modern polyphasic methods that include MALDI-TOF analyses for fungal identifications and authentications

Publication . Lima, Nelson; Rodrigues, Paula; Soares, Célia; Santos, Cledir; Paterson, Russell; Venâncio, Armando

The identification of species is an important goal in taxonomic mycology. Information about each fungus (e.g. morphological description, physiological and biochemical properties, ecological roles, and societal risks or benefits) is the key element in this process. Identifications can be a long and seemingly never-ending process with frequent revisions of the taxonomic schemes. These changes make identifications even more complicated for the non specialised researchers as each taxonomic group has specialized literature, terminology and characters. This occurs to the extend that identifications can only be undertaken by a narrow group of scientists especially skilled in the "art", which can make the procedures appear to be subjective.

2008Conference object

Open access

Taxonomy of Aspergillus: integration of methods for new and revisited species in section Flavi

Publication . Rodrigues, Paula; Soares, Célia; Santos, Cledir; Venâncio, Armando; Lima, Nelson

Aspergillus is a large genus and, as with fungi in general, its taxonomy is complex and ever evolving. Section Flavi is one of the most significant sections of the genus, for it comprises two distinct groups of species with great interest to food industry: one group includes the aflatoxigenic species, which cause serious problems in agricultural commodities, and the other includes the non-aflatoxigenic species traditionally used in food fermentation and biotechnological processes. Because of the significant phenotypic and genetic similarity between species, taxonomy and species identification within this section has always been subject of great interest for scientists who struggle to clarify the species concept and delimitations within the section, and to find a consistent and stable taxonomic scheme. Throughout the last decades, the taxonomy of Aspergillus has evolved from a simple morphological species concept to a more complex scheme also integrating biochemical, ecological, genetic and molecular traits. Also, as methods become more sensitive, accurate and widespread, species are constantly being added or re-classified or even repositioned within the genus. We are here in presenting a comprehensive work on the identification of large numbers of Portuguese isolates from Section Flavi through the combination of various methods, including morphological, biochemical and molecular ones, as well as the novel approach based on spectral analysis by MALDI-TOF-ICMS. By applying this polyphasic scheme of identification, we were able to identify and characterise three new aflatoxigenic species within this section.

2012Conference object

Open access