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

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

Cost-effective bioethanol production at low content of nitrogen source from carob syrup

Ethanol, as biofuel, has received great interest in the latest decades due to its potential as an alternative transport fuel. Nowadays, ethanol can be produced through fermentative processes, using sugar rich agricultural raw material and it may have a significant role in reducing environmental impact of fossil fuels

A polyphasic approach for black Aspergillus identification using MALDI-TOF MS

The Aspergillus section Nigri is among the best studied fungi, having different commercial applications, but also causing biodeterioration of commodities and food spoilage. Although being well studied, their identification is not straightforward, and, recently, new species have been described in this section. These new species were not only separated from their relatives in the section by morphological distinction but also from molecular point of view. Recently, Matrix-Assisted Laser Desorption/Ionisation Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) has been used to generate spectrum of protein masses in a range of 2000 to 20000 Da that is a taxon specific fingerprinting. This approach could be employed as an alternative to the molecular techniques

Micotoxinas: contributos da Micoteca da Universidade do Minho (MUM) para a segurança alimentar.

A 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

Kinetic and energetic parameters of carob wastes fermentation by Saccharomyces cerevisiae: crabtree effect, ethanol toxicity, and invertase repression

Carob waste is a useful raw material for the second-generation ethanol because 50% of its dry weight is sucrose, glucose, and fructose. To optimize the process, we have studied the influence of the initial concentration of sugars on the fermentation performance of Saccharomyces cerevisiae. With initial sugar concentrations (S0) of 20 g/l, the yeasts were derepressed and the ethanol produced during the exponential phase was consumed in a diauxic phase. The rate of ethanol consumption decreased with increasing S0 and disappeared at 250 g/l when the Crabtree effect was complete and almost all the sugar consumed was transformed into ethanol with a yield factor of 0.42 g/g. Sucrose hydrolysis was delayed at high S0 because of glucose repression of invertase synthesis, which was triggered at concentrations above 40 g/l. At S0 higher than 250 g/l, even when glucose had been exhausted, sucrose was hydrolyzed very slowly, probably due to an inhibition at this low water activity. Although with lower metabolic rates and longer times of fermentation, 250 g/l is considered the optimal initial concentration because it avoids the diauxic consumption of ethanol and maintains enough invertase activity to consume all the sucrose, and also avoids the inhibitions due to lower water activities at higher S0.Project Alfaetilico, as part of the Portuguese National Program QREN-POAlgarve21info:eu-repo/semantics/publishedVersio

Identification and characterization of Aspergillus flavus and aflatoxins

Aspergillus flavus is the main producer of the well known carcinogenic aflatoxins. The presence of this fungus and aflatoxins is of huge concern in terms of food safety. The identification of A. flavus is not straightforward due to similarities with closely related species (e.g. A. parasiticus and A. nomius). Also, from the biochemical point of view the closely-related species are able to produce different mycotoxins. In order to clarify the differentiation between species the identification schemes is revisited. Selective media, data from mycotoxins production and molecular biology tools are discussed in order to clarify the concept of A. flavus species.Fundação para a Ciência e a Tecnologia (FCT

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

[Excerpt] 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. [...

Three new aflatoxigenic species of Aspergillus section Flavi isolated in Portugal

PosterThree 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.Fundação para a Ciência e a Tecnologia (FCT

Efetividade de escovas dentais de baixo custo, com ou sem o uso de dentifrício, na remoção da placa bacteriana em dentes decíduos

O principal objetivo deste estudo foi comparar a efetividade de uma escova dental de baixo custo (monobloco) à efetividade de uma escova convencional, com ou sem adição de dentifrício, em relação à remoção da placa dentária.Participaram deste estudo trinta e duas crianças de 4 a 6 anos de idade, que foram avaliadas sob quatro condições experimentais, definidas pela combinação de dois fatores: escova dental (convencional ou monobloco) e uso de dentifrício (com ou sem dentifrício). A efetividade dos tratamentos foi definida em termos de redução do índice de placa bacteriana, avaliado antes e após a escovação.Não foram encontradas diferenças estatisticamente significativas entre os dois tipos de escovas no que diz respeito à redução de placa bacteriana. Similarmente, não houve evidências estatísticas de que o uso de dentifrício aumenta o controle mecânico da placa. Esses resultados são importantes do ponto de vista de saúde pública, principalmente em países em desenvolvimento, onde a disseminação de técnicas educacionais e preventivas de baixo custo são fundamentais.The main objective of this study was to compare the effectiveness of a low cost toothbrush ("monoblock") to that of a conventional toothbrush with and without addition of dentifrice with respect to the removal of dental plaque. Thirty-two 4- to 6-year-old children took part in this study: they were evaluated under four experimental conditions defined by the combinations of the values of two factors, toothbrush (conventional or monoblock) and use of dentifrice (with or without). The effectiveness of the treatments was defined in terms of the reduction of a bacterial plaque index evaluated before and after toothbrushing. No statistically significant differences were detected between the two types of toothbrushes with respect to the reduction of the bacterial plaque index. Similarly, there were no statistical evidences that the use of dentifrice improves the mechanical control of dental plaque. These results are important from a public health point of view, specially in developing countries, where the dissemination of educational and preventive techniques of low cost are fundamental

Food mycology : from the fork to the farm

Filamentous fungi are ubiquitous in nature and are responsible for producing mycotoxins in agricultural crops. Fungi and mycotoxins are considered generally as being natural and unavoidable [1]. The control and detection of mycotoxins is a continuous process in commodity production. Since mycotoxins can become established and remain within the commodity anywhere throughout the production, storage, transportation and processing chain, there is a need to study all the food chain: from the fork to the farm. The control over the presence of mycotoxins involves several competencies, such as taxonomy skills, ability to evaluate mycotoxins production by fungi, and ability to quantify mycotoxins in commodities. The prevention of mycotoxin formation is achieved by influencing environmental conditions through management of agricultural practices prior to harvest. After harvest, two overriding factors for storage are water activity (aw) and temperature. Control over these parameters may lead to the prevention of fungi growth and of mycotoxins accumulation. Strategies followed to have control over the presence of mycotoxins in commodities will be illustrated by presenting case studies: (i) ochratoxin A in wine; and (ii) aflatoxins in maize and in nuts