Browsing by Author "Freitas-Silva, Otniel"
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- Contributions of Micoteca da Universidade do Minho to food mycologyPublication . Rodrigues, Paula; Soares, Célia; Freitas-Silva, Otniel; Santos, Cledir; Paterson, Russell; Kozakiewicz, Zofia; Venâncio, Armando; Lima, NelsonMicoteca da Universidade do Minho (MUM) is a collection of fungi established in 1996. Research involving secondary metabolites in the form of mycotoxins is paramount. An objective is to provide authentic strains for research in biotechnology, life sciences and challenge testing. Knowledge, information and training in mycology are promulgated by the biological resource centre. MUM is involved in projects which address the health and quality risks from fungal contamination of grape products (e.g. wine), apples, cheese, chilies, nuts and corn: Fungi in drinking water is of particular concern. Aspergillus ochraceous, Aspergillus flavus, Penicillium expansum and Fusarium graminearum especially are relevant to our work: Associated mycotoxins are ochratoxin A, aflatoxins, patulin, citrinin and zearalenone. We study the earthy off-flavours in wine from Botrytis cinearum and P. expansum. The analytical techniques employed are PCR, HPLC, GC-MS and MALDITOF MS for strain characterization. MUM participates in several European and national projects. Post-graduate studies on mycotoxigenic fungi and food security particularly are important. A key objective is international collaboration. MUM strains are well characterized for toxigenicity, making the collection relevant to its mission and industry. This presentation will describe the progress made in this innovative Portuguese laboratory over 10 years.
- HPLC method for simultaneous detection of aflatoxins and cyclopiazonic acidPublication . Soares, Célia; Rodrigues, Paula; Freitas-Silva, Otniel; Abrunhosa, Luís; Venâncio, ArmandoAspergillus species in section Flavi are among the most relevant mycotoxigenic fungi. The organisms are well-known producers of the highly carcinogenic aflatoxins and of other mycotoxins, such as cyclopiazonic acid. Aflatoxins and cyclopiazonic acid analyses can be routinely used for identification purposes within the section. Two separate chromatographic runs with distinct columns and detectors for each toxin were required in previous reports. A straightforward high performance liquid chromatography (HPLC) procedure for the simultaneous detection of these compounds in fungal cultures was developed in the present work using a methanol/water mobile phase, post-column photochemical derivatisation and fluorescence detection. The proposed method was tested with standards and fungal extracts of 24 Aspergillus section Flavi strains and compared to the common individual detection of these mycotoxins by HPLC analyses.
- Liquid chromatography for multimycotoxin detection for filamentous fungi identificationPublication . Soares, Célia; Rodrigues, Paula; Freitas-Silva, Otniel; Abrunhosa, Luís; Venâncio, ArmandoMycotoxins are secondary metabolites produced by specific filamentous fungi. Among the most relevant mycotoxigenic producer fungi are some Aspergillus species such as the ones belonging to the Aspergillus section Flavi. These are known to produce the highly carcinogenic aflatoxins (AFB1, AFB2; AFG1 and AFG2) and cyclopiazonic acid (CPA) in agricultural commodities. Besides the issues related to food safety, aflatoxins and CPA analysis can also be routinely used for identification purposes within the Aspergillus section Flavi, since the various species exhibit different mycotoxin profiles. Aflatoxins are mainly produced by some strains of Aspergillus flavus and Aspergillus nomius and by all strains of Aspergillus parasiticus, whereas CPA is mainly produced by Aspergillus flavus strains. The aim of this study was to develop a rapid HPLC method that could detect simultaneously both these mycotoxins. For this purpose twenty two strains belonging to Aspergillus section Flavi were tested for aflatoxins and CPA production. Extracts were analysed using a HPLC system. The tested methodology allowed the separation of CPA from AFGs and AFBs in a HPLC single run and proved to be a useful tool for helping in the identification of the strains in study. Data from these assays will be presented and discussed.
- Micotoxinas: contributos da micoteca da Universidade do Minho (mum) para a segurança alimentarPublication . Rodrigues, Paula; Soares, Célia; Freitas-Silva, Otniel; Santos, Cledir; Paterson, Russell; Kozakiewicz, Zofia; Venâncio, Armando; Lima, NelsonA Micoteca da Universidade do Minho (MUM), fundada em 1996, tem como missão ser uma colecção de fungos filamentosos com o objectivo principal de manter e fornecer estirpes com qualidade e autenticidade para a investigação em biotecnologia e ciências da vida, e laboratórios de ensaio, actuando também como um centro de conhecimento, informação e formação na área da micologia. Dentro desta missão, a MUM tem estado envolvida em projectos que procuram dar resposta aos riscos alimentares derivados da contaminação fúngica.
- Micotoxinas: contributos da Micoteca da Universidade do Minho (MUM) para a segurança alimentar.Publication . Rodrigues, Paula; Soares, Célia; Freitas-Silva, Otniel; Santos, Cledir; Paterson, Russell; Venâncio, Armando; Lima, NelsonA Micoteca da Universidade do Minho (MUM), fundada em 1996, tem como missão ser uma colecção de fungos filamentosos com o objectivo principal de manter e fornecer estirpes com qualidade e autenticidade para a investigação em biotecnologia e ciências da vida, e laboratórios de ensaio, actuando também como um centro de conhecimento, informação e formação na área da micologia. Dentro desta missão, a MUM tem estado envolvida em projectos que procuram dar resposta aos riscos alimentares derivados da contaminação fúngica.
- Rapid HPLC method for simultaneous detection of aflatoxins and cyclopiazonic from Aspergillus section FlaviPublication . Soares, Célia; Rodrigues, Paula; Freitas-Silva, Otniel; Abrunhosa, Luís; Venâncio, ArmandoMycotoxins 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.