1,720,965 research outputs found
Ochratoxin A production by Aspergillus niger: Effect of water activity and a biopreserver formulated with Lactobacillus plantarum CRL 778
Get PDFSome filamentous fungi of the genera Aspergillus (A.) are of high impact in food safety due to the production of a toxic secondary metabolite, the ochratoxin A (OTA). The present study was carried out to evaluate the effect water activity (aw) on the growth and the OTA production by the strain Aspergillus niger 13D both invitro assays and in bread slices. High values of aw favoured growth and OTA production by A.niger 13D in Czapek Yeast extract agar medium (CYA) with the optimum at 0.995. In bread slices, fungi growth rate (μmax: 0.90-1.07cmd-1) and OTA production (5.13-10.79ngg-1) were lower respect to CYA medium (μmax: 1.09-1.81cmd-1, OTA concentration: 26.02-133.28ngg-1) independently to aw. Furthermore, efficacy antifungal of biopreserver formulated with Lactobacillus plantarum CRL 778 (SL778) for packed bread was evaluated. Our result evidenced the inhibitory activity of SL778 against growth of ochratoxigenic A.niger 13D in bread making at different aw. In addition, this biopreserver demonstrated is principally antimycotoxigenic, observing a reduction 60% of OTA at 0.995 and 0.971 aw in bread added with SL778.Fil: Gerez, Carla Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Dallagnol, Andrea Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Ponsone, Maria Lorena. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología. Cátedra de Micología; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología. Cátedra de Micología; ArgentinaFil: Font, Graciela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin
Effect of water activity and temperature on growth of Aspergillus carbonarius and Aspergillus tubingensis and their interactions on ochratoxin a production
Get PDFAspergillus section Nigri are described as the main source of ochratoxin A (OTA) contamination in grapes and wine worldwide. The grape-growing area in Argentina has a wide latitudinal extension with ecological variations that allow the classification of well-demarcated regions. The aims of this study were: to determine the effect of eco-physiological parameters on growth of Aspergillus tubingensis and Aspergillus carbonarius and to evaluate the interaction between these species on OTA production in synthetic grape juice medium under different water activity (aw) and temperature conditions. The results showed that optimal growth conditions for A. tubingensis and A. carbonarius were 0.980 awand 28 °C, however A. tubingensis grew faster than A. carbonarius at all temperatures and awtested. OTA production by A. carbonarius was favoured at 20 °C and 0.950-0.965 aw, during 14 days of incubation. The effect of A. tubingensis on OTA production by A. carbonarius was mainly dependent on temperature. At 35 °C, A. tubingensis reduced the OTA production while this effect was not observed at 20 °C. More OTA could be produced as a defence reaction against fungal competitors to maintain niche colonisation, but in this study no effects by a related species were observed.Fil: Chiotta, María Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosa, Débora María. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ponsone, Maria Lorena. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Biocontrol of postharvest Alternaria decay in table grapes from Mendoza province
No full textPostharvest diseases cause considerable loss of fruit during transportation and storage. Synthetic fungicides are primarily used to control them. However, the recent trend is to shift toward safer and more eco-friendly alternatives for the control of postharvest decays. In Argentina, Alternaria genus was cited as a postharvest pathogen on table grapes for the first time during 2010–2012 seasons. The aim of this study was to identify, by morphological and molecular techniques, Alternaria spp. strains isolated from table grapes cv. Red Globe in different phenological stages of vine and postharvest storage in Mendoza province. In addition, we intended to propose an alternative postharvest management to the use of sulfur dioxide (SO2) generators (traditional method). We searched for a lower environmental impacting substitute using the yeast strain Metschnikowia pulcherrima RCM2 and chitosan coatings as possible control agents. The results showed that the pathogen was present in all the stages studied and the 100% of the strains belonged to the species-group Alternaria alternata. Besides, chitosan coatings showed to be a good alternative method to SO2 generators. This work is focus on the study of the incidence of Alternaria spp. during the phenological cycle and postharvest storage of table grapes cv. Red Globe, and also on the evaluation of alternative strategies to the use of SO2 for the control of this disease during the extended cold storage.Fil: Stocco, Antonella Fabia. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Diaz, Mariano Emanuel. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Rodríguez Romera, M.C.. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; ArgentinaFil: Mercado, Laura Analia. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Rivero, María Laura. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; ArgentinaFil: Ponsone, Maria Lorena. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Mendoza-san Juan. Estacion Experimental Agropecuaria Mendoza. Agencia de Extension Rural Lujan de Cuyo.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin
Biodiversity of Aspergillus section Nigri populations in Argentinian vineyards and ochratoxin A contamination
Get PDFAspergillus section Nigri are described as the main source of ochratoxin A(OTA) contamination in grapes and wine worldwide. The knowledge of the factors affecting grape contamination by species included in this section and OTA production is essential to be able to reduce their presence, not only to improve wine quality, but also to maintain their safety. Therefore, the aims of this study were to determine the incidence of Aspergillus section Nigri species harvested in different grape-growing regions from Argentina, their ability to produce OTA, to correlate with meteorological conditions and geographical coordinates with their prevalence and to evaluate the OTA natural occurrence in grapes and wines. The morphological identification showed that A. niger aggregate species were the most prevalent ones, followed by A. carbonarius and Aspergillus uniseriate. These populations were confirmed through using AFLP markers and sequencing and, A. tubingensis was separated from A. niger aggregate. Climatic factors, altitude, longitude and latitude have influenced on the distribution of species included in the section. A. carbonarius and A. niger were OTA producers but differed in their OTA producing ability. Temperature was the factor which influenced the most over the highest incidence of A. carbonarius in La Rioja and San Juan regions. The trellis system in vineyards and drip irrigation also influenced the species isolation. The OTA levels detected in grapes and wines were low, but grape variety was more important in susceptibility to fungal infection and OTA levels.Fil: Chiotta, María Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba; ArgentinaFil: Ponsone, Maria Lorena. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología. Cátedra de Micología; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Sosa, Débora María. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Biología Molecular. Sección Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba; ArgentinaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Cuyo Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza. Centro de Estudios Enológicos; ArgentinaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentin
Recent advances in biocontrol and other alternative strategies for the management of postharvest decay in table grapes
No full textDuring postharvest, table grapes are often spoiled by molds. Aspergillus sp., Alternaria sp., Botrytis sp., Cladosporium sp. and Penicillium sp. are different mold genera frequently related to table grape rot. Fungal spoilage affects nutritional value and organoleptic properties while also producing health hazards, such as mycotoxins. Traditionally, synthetic fungicides have been employed to control fungal diseases. However, possible negative effects on health and the environment are a serious concern for consumers and government entities. This review summarized data on innovative strategies proposed to diminish postharvest losses and extend table grape shelf life. Among physical, chemical, and biological strategies, either alone or in combination, the integrated management of fungal diseases is a sustainable alternative to synthetic fungicides. However, to date, only a few alternative technologies have succeeded on a commercial scale. Recent research aimed at increasing the competitiveness of alternative technologies has led to the development of integrated management strategies to prevent postharvest decay and increase the safety and quality of table grapes.Fil: Torres Palazzolo, Carolina Andrea. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; Argentina. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ferreyra, Susana Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Hugalde, Ines Pilar. Universidad Nacional de Cuyo; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Kuhn, Yamila Gisele. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ponsone, Maria Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria Mendoza; Argentin
Effect of Kluyveromyces thermotolerans on polyketide synthase gene expression and ochratoxin accumulation by Penicillium and Aspergillus
No full textIn a previous study, it was demonstrated that Kluyveromyces thermotolerans strains can reduce both growth and ochratoxin A (OTA) accumulation by Aspergillus section Nigri strains. There is no information about the mechanisms related to this reduction. A viable hypothesis can be that the presence of biocontrol agents can affect OTA biosynthesis by influencing the transcriptional activity of the polyketide synthase (pks) gene, one of the key enzymes in the OTA biosynthetic pathway. The aims of this work were to determine the effect of two selected strains of K. thermotolerans as potential biocontrol agents and to evaluate if their presence can affect the otapks gene expression of ochratoxigenic Aspergillus and Penicillium species. Growth, OTA and ochratoxin B (OTB) biosynthesis by the fungal strains at the phenotypic and molecular levels were monitored. The results obtained showed that both K. thermotolerans strains evaluated had a strong influence on growth, OTA and OTB biosynthesis, and expression of the mycotoxin biosynthesis genes. However, no direct correlation between the influence of the biocontrol yeasts on pks gene expression, OTA and OTB production could be found. These results could indicate an inhibitory mechanism by the yeasts, which apparently involve a post-transcriptional mechanism. The data obtained could imply that the production of mycotoxins can be regarded as a kind of adaptation mechanism to environmental stress conditions by these mycotoxigenic species.Fil: Ponsone, Maria Lorena. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kuhn, Yamila Gisele. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schmidt Heydt, M.. Max Rubner Institut; AlemaniaFil: Geisen, R.. Max Rubner Institut; AlemaniaFil: Chulze, Sofia Noemi. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Microbiología e Inmunología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Incidence of osmophilic yeasts and Zygosaccharomyces rouxii during the production of concentrate grape juices
Get PDFZygosaccharomyces rouxii is the main spoilage yeast of grape juice concentrates. Detection and identification of Z. rouxii during the production of grape juice concentrate is critical to prevent spoilage in the final product. In this work, three grape juice concentrate processing plants were assessed by identifying osmophilic yeasts in juices and surfaces during different stages of a complete production line. Subsequently, molecular typing of Z. rouxii isolates was done to determine the strain distribution of this spoilage yeast. Osmotolerant yeast species, other than Z. rouxii, were mainly recovered from processing plant environments. Z. rouxii was only isolated from surface samples with grape juice remains. Z. rouxii was largely isolated from grape juice samples with some degree of concentration. Storage of grape juice pre-concentrate and concentrate allowed an increase in the Z. rouxii population. A widely distributed dominant molecular Z. rouxii pattern was found in samples from all three processing plants, suggesting resident microbes inside the plant.Fil: Rojo, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: Torres Palazzolo, Carolina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Cuello, Raúl Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: González, Magalí Lucía Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: Guevara, F.. Universidad de Santiago de Chile; ChileFil: Ponsone, Maria Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: Mercado, Laura Analia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; ArgentinaFil: Martínez, C.. Universidad de Santiago de Chile; ChileFil: Combina, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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