Person:
González Jaén, María Teresa

First Name

María Teresa

Last Name

González Jaén

URI

https://hdl.handle.net/20.500.14352/74413

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Biológicas

Department

Genética, Fisiología y Microbiología

Area

Genética

Identifiers

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Now showing 1 - 10 of 17

Description of an orthologous cluster of ochratoxin A biosynthetic genes in Aspergillus and Penicillium species. A comparative analysis
(International Journal of Food Microbiology, 2018) Gil-Serna, Jessica; García-Díaz, Marta; González Jaén, María Teresa; Vázquez Estevez, Covandonga; Patiño Álvarez, Belén
Ochratoxin A (OTA) is one of the most important mycotoxins due to its toxic properties and worldwide distribution which is produced by several Aspergillus and Penicillium species. The knowledge of OTA biosynthetic genes and understanding of the mechanisms involved in their regulation are essential. In this work, we obtained a clear picture of biosynthetic genes organization in the main OTA-producing Aspergillus and Penicillium species (A. steynii, A. westerdijkiae, A. niger, A. carbonarius and P. nordicum) using complete genome sequences obtained in this work or previously available on databases. The results revealed a region containing five ORFs which predicted five proteins: halogenase, bZIP transcription factor, cytochrome P450 monooxygenase, non-ribosomal peptide synthetase and polyketide synthase in all the five species. Genetic synteny was conserved in both Penicillium and Aspergillus species although genomic location seemed to be different since the clusters presented different flanking regions (except for A. steynii and A. westerdijkiae); these observations support the hypothesis of the orthology of this genomic region and that it might have been acquired by horizontal transfer. New real-time RT-PCR assays for quantification of the expression of these OTA biosynthetic genes were developed. In all species, the five genes were consistently expressed in OTA-producing strains in permissive conditions. These protocols might favour futures studies on the regulation of biosynthetic genes in order to develop new efficient control methods to avoid OTA entering the food chain.
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, Salem
Wheat, 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.
Targeting conserved genes in fusarium species
(Mycotoxigenic Fungi: Methods and Protocols, 2017) Gil-Serna, Jessica; Patiño Álvarez, Aurora Belén; Jurado, Miguel; Mirete Castañeda, Salvador; Vázquez Estévez, Covadoga; González Jaén, María Teresa
Fumonisins are important mycotoxins contaminating foods and feeds which are mainly produced by F. verticillioides and F. proliferatum. Additionally, both are pathogens of maize and other cereals. We describe two highly sensitive, rapid, and species-specific PCR protocols which enable detection and discrimination of these closely related species in cereal flour or grain samples. The specific primer pairs of these assays were based on the intergenic spacer region of the multicopy rDNA unit which highly improves the sensitivity of the PCR assay in comparison with single-copy target regions.
Evaluation of growth and ochratoxin A production by Aspergillus steynii and Aspergillus westerdijkiae in green-coffee based medium under different environmental conditions
(Food research international, 2014) Gil-Serna, Jessica; Vázquez Estévez, Covadoga; García Sandino, Fernando; Márquez Valle, Ana; González Jaén, María Teresa; Patiño Álvarez, Belén
Aspergillus steynii and Aspergillus westerdijkiae are important ochratoxin A (OTA)-producing species frequently found in coffee. Although the processing of green coffee beans reduces markedly OTA contamination, levels exceeding the legal limitsmight remain in the final product. Environmental conditions are a crucial factor affecting growth and OTA production in fungal species; therefore, in thiswork,we analysed the effect of different levels of temperature (23, 28, 32, 37, 42 °C) andwater activity (aw) (0.89, 0.91, 0.93, 0.95, 0.97, 0.99) on growth and toxin production by A. steynii and A. westerdijkiae in green coffee-based medium. A. steynii was able to grow and produce OTA in a wider set of conditions than A. westerdijkiae. A new index (OTA risk index) has been described to integrate both fungal growth and OTA production and, according to it, A. steynii would pose a higher risk of OTA contamination in coffee than A. westerdijkiae at all the conditions tested. Neither A. steynii nor A. westerdijkiae were able to grow at the lowest value of aw (0.89) evaluated and OTA production was extremely low at 0.91. Therefore, the application of good practices during storage aiming to maintain low humidity levelsmight be essential to prevent OTA contamination in coffee at this stage. The optimal conditions of both species to grow and produce OTA were established at warm temperatures (28–32 °C) and high aw levels. Therefore, these species could be considered well-adapted in predicted climate change scenarios resulting in a potential high risk source of OTA contamination for this product.
Wine Contamination with Ochratoxins: A Review
(Beverages, 2018) Gil Serna, Jéssica; Vázquez Estévez, Covadonga; González Jaén, María Teresa; Patiño Álvarez, Belén
Ochratoxin A (OTA) is the main mycotoxin occurring in wine. This review article is focused on the distribution of this toxin and its producing-fungi in grape berries, as well as on the fate of OTA during winemaking procedures. Due to its toxic properties, OTA levels in wine are regulated in different countries; therefore, it is necessary to apply control and detoxification methods that are also discusse in this revision.
Métodos alternativos al control químico de hongos toxígenos y micotoxinas en alimentos
(ANS. Alimentación nutrición y salud, 2014) Gil-Serna, Jessica; Patiño Álvarez, Belén; Vázquez Estévez, Covadoga; González Jaén, María Teresa
Las micotoxinas son un grave riesgo para la seguridad alimentaria y es imprescindible controlar su presencia en alimentos. Tradicionalmente, se han aplicado compuestos químicos para evitar el desarrollo de los hongos productores aunque, en los últimos años, se ha restringido mucho su uso debido a los problemas que ocasionan para la salud y el medio ambiente y a la restrictiva legislación Europea. En este trabajo, se ha evaluado la efectividad in vitro de métodos alternativos (antioxidantes, aceites esenciales y control biológico con microorganismos antagónicos) para controlar el crecimiento y la producción de micotoxinas de importantes especies del género Aspergillus. Los extractos de salvia española y espliego, así como el agente biológico Debaryomyces hansenii CYC 1244 han demostrado ser prometedores candidatos para la reducción de la contaminación por micotoxinas en alimentos al ser capaces de reducir significativamente el desarrollo y la producción de micotoxinas en varias de especies toxígenas.
Significance of Aspergillus nigeraggregate species as contaminants of food products in Spain regarding their occurrence and their ability to produce mycotoxins
(Food Microbiology, 2019) Gil-Serna, Jessica; García-Díaz, Marta; Vázquez, Covadonga; González Jaén, María Teresa; Patiño Álvarez, Belén
The Aspergillus niger aggregate contains 15 morphologically indistinguishable species which presence is related to ochratoxin A (OTA) and fumonisin B2 (FB2) contamination of foodstuffs. The taxonomy of this group was recently reevaluated and there is a need of new studies regarding the risk that these species might pose to food security. 258 isolates of A. niger aggregate obtained from a variety of products from Spain were classified by molecular methods being A. tubingensis the most frequently occurring (67.5%) followed by A. welwitschiae (19.4%) and A. niger (11.7%). Their potential ability to produce mycotoxins was evaluated by PCR protocols which allow a rapid detection of OTA and FB2 biosynthetic genes in their genomes. OTA production is not widespread in A. niger aggregate since only 17% of A. niger and 6% of A. welwitschiae isolates presented the complete biosynthetic cluster whereas the lack of the cluster was confirmed in all A. tubingensis isolates. On the other hand, A. niger and A. welwitschiae seem to be important FB2 producers with 97% and 29% of the isolates, respectively, presenting the complete cluster. The genes involved in OTA and FB2 were overexpressed in producing isolates and their expression was related to mycotoxin synthesis.
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 Teresa
Fusarium 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.
Project number: 65
Creación del primer Grupo iGEM (Competición Internacional de Biología Sintética) de Madrid: Facultad de Biología-UCM
(2019) Marquina Díaz, Domingo; Santos de la Sen, Antonio; Alonso Conde, Rafael Alejandro; González Jaén, María Teresa; Quero Lombardero, Francisco Javier; Gómez Flechoso, Mª de los Ángeles; Saiz Gonzalo, Gonzalo; Martín González, Ana María; Belda Aguilar, Ignacio; Armero Hernández, Laura; Serrano Barrero, Susana Lourdes
En este Trabajo se describe la creación del primer Grupo iGEM de Madrid así como la elaboración de un biosensor que permite la detección de polen de olivo a tiempo real empleando metodos de ingeniería genética y robótica.
Phylogenetic analysis and growth profiles of Fusarium incarnatum-equiseti species complex strains isolated from Tunisian cereals
(International Journal of Food Microbiology, 2021) Jedidi, Ines; Jurado, Miguel; Cruz, Alejandra; Mounir, Mohamed Trabelsi; Said, Salem; González Jaén, María Teresa
The Fusarium incarnatum-equiseti species complex (FIESC) is a phylogenetically rich complex. It includes more than 30 cryptic phylogenetic species, making morphological identification problematic. FIESC has previously been detected in Tunisian cereals, but knowledge on the phylogeny and the ecophysiology of their species is lacking. In this work a phylogenetic analysis was performed using partial sequences of the translation elongation factor 1a gene (EF1a) of three FIESC strains isolated from barley and wheat from Tunisia, situated south in the Mediterranean basin, and additional strains from other countries. The results indicated that all Tunisian strains clustered with FIESC 5 group (F. clavum) together with other Spanish FIESC 5 strains also isolated from cereals. Growth rate profiles of the Tunisian strains were also determined on wheat and sorghum based media at a range of temperatures (15, 20, 25, 30, 35 and 40 ◦C) and water potential values (− 0.7, − 2.8, − 7.0, and − 9.8 MPa, corresponding to 0.995, 0.98, 0.95 and 0.93 aw values). Optimal growth was observed at 20–30 ◦C and between − 0.7 and − 7.0 MPa on both substrates (wheat and sorghum). The highest growth rate for the three strains was seen at 25 ◦C combined with − 2.8 MPa. The comparison between the growth profiles of Tunisian and Spanish FIESC 5 strains showed similar trends with some interesting differences regarding temperature and water potential factors. Tunisian strains seem to perform better between 15 and 30 ◦C and, notably, at even lower water potentials included − 9.8 Mpa. This might suggest that tolerance to low water potentials might be for Tunisian strains a more important selective clue than to higher temperatures. These results appeared to be consistent with a population well adapted to the present climatic conditions and predicted scenarios for North Africa.