Person: González Jaén, María Teresa
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First Name
María Teresa
Last Name
González Jaén
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Genética
Identifiers
3 results
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Item Mycoflora isolation and molecular characterization of Aspergillus and Fusarium species in Tunisian cereals(Saudi Journal of Biological Sciences, 2017) Jedidi, Ines; Soldevilla, Carlos; Lahouar, Amani; Marín, Patricia; González Jaén, María Teresa; Said, SalemWheat, barley and maize are the mainly consumed cereals in Tunisia. This study aimed to determine the mycoflora of these cereals with special focus on the mycotoxigenic Aspergillus and Fusarium species. Freshly harvested samples and other stored samples of each type of cereal (31 and 34 samples, respectively) were collected in Tunisia and cultured for fungal isolation and identification. Identification of fungal genera was based on morphological features. Aspergillus and Fusarium species were identified by species specific PCR assays complemented with DNA sequencing. Alternaria (70.83%), Eurotium (62.50%), Aspergillus (54.17%) and Penicillium (41.67%) were the most frequent fungi isolated from wheat. Penicillium (75%), Aspergillus (70%), Eurotium (65%) and Alternaria (65%) were the most frequently recovered genera from barley. The predominant genera in maize were Aspergillus(76.19%), Eurotium (42.86%), and Penicillium (38.09%). Aspergilllus, Penicillium, Fusarium and Alternaria were detected in both stored and freshly harvested grain samples. The frequencies of contamination with Aspergillus, Fusarium and Alternaria were higher in freshly harvested samples, whereas Penicillium species were more frequent in stored samples. The predominant Aspergillus species detected were A. flavus and A. niger. The Fusarium species detected were F. equiseti, F. verticillioides, F. nygamai, and F. oxysporum. This study suggested the potential risk for Aflatoxins and, to a lesser extent, for Ochratoxin A in Tunisian cereals. This is the first survey about mycoflora associated with wheat, barley and maize in Tunisia.Item Growth rate and TRI5 gene expression profiles of Fusarium equiseti strains isolated from Spanish cereals cultivated on wheat and barley media at different environmental conditions(International Journal of Food Microbiology, 2015) Marín, Patricia; Jurado, Miguel; González Jaén, María TeresaFusarium equiseti is a toxigenic species that often contaminates cereal crops from diverse climatic regions such as Northern and Southern Europe. Previous results suggested the existence of two distinct populations within this species with differences in toxin profile which largely corresponded to North and South Europe (Spain). In this work, growth rate profiles of 4 F. equiseti strains isolated from different cereals and distinct Spanish regions were determined on wheat and barley based media at a range of temperatures (15, 20, 25, 30, 35 and 40 °C) and water potential regimens (− 0.7, − 2.8, − 7.0, and − 9.8 MPa, corresponding to 0.99, 0.98, 0.95 and 0.93 aw values). Growth was observed at all temperatures except at 40 °C, and at all the solute potential values except at − 9.8 MPa when combined with 15 °C. Optimal growth was observed at 20–30 °C and − 0.7/− 2.8 MPa. The effect of these factors on trichothecene biosynthesis was examined on a F. equiseti strain using a newly developed real time RT-PCR protocol to quantify TRI5 gene expression at 15, 25 and 35 °C and − 0.7, − 2.8, − 7.0 and − 9.8 MPa on wheat and barley based media. Induction of TRI5 expression was detected between 25 and 35 °C and − 0.7 and − 2.8 MPa, with maximum values at 35 °C and − 2.8 MPa being higher in barley than in wheat medium. These results appeared to be consistent with a population well adapted to the present climatic conditions and predicted scenarios for Southern Europe and suggested some differences depending on the cereal considered. These are also discussed in relation to other Fusarium species co-occurring in cereals grown in this region and to their significance for prediction and control strategies of toxigenic risk in future scenarios of climate change for this region.Item Aflatoxins and ochratoxin A and their Aspergillus causal species in Tunisian cereals(Food Additives & Contaminants: Part B, 2016) Jedidi, Ines; Cruz, Alejandra; González Jaén, María Teresa; Said, SalemOccurrence of aflatoxins (AFs) AFB1, AFB2, AFG1, AFG2 and ochra toxin A (OTA) was studied in 65 samples of stored and freshly harvested wheat, barley and maize collected in Tunisia. The mycotoxins were simultaneously extracted and quantified by high performance liquid chromatography. Determination of AF-producing (section Flavi) and OTA-producing Aspergillus species (sections Nigri and Circumdati) was conducted in these samples by species-specific polymerase chain reaction (PCR). Results showed that most of maize samples were contaminated with AFs, data after storage showing lower values than those collected at harvest. All contaminated maize samples contained AFG1 and AFG2, among which 27.78% also had AFB1 and AFB2. This AFs pattern was consistent with the A. parasiticus toxin profile. A. flavus however showed the highest frequency in maize but was also found in barley and wheat where no AFs were detected. In contrast, OTA was neither found in maize nor in barley and only one wheat sample contained OTA. A. niger was the only OTA-producing species detected.