1,720,966 research outputs found
Combined effect of beauvericin and T-2 toxin on antioxidant defence systems in cherry tomato shoots
No full textDuring their life cycle, plants can undergo simultaneous attack by different pathogens that produce various toxins. It is well known that in some plant-fungal interactions, mycotoxins play an important role in pathogenesis and induce a reactive oxygen species (ROS) increase. Plants counteract the over-accumulation of ROS by reinforcing the defence systems. T-2 toxin (T-2) and beauvericin (BEA) mycotoxins are produced by some Fusarium species and have different chemical structures, mechanisms of action and biological activities. In this study, the individual and combined effects of the two toxins on defence systems such as the ascorbate-glutathione cycle and peroxidases were evaluated in cherry tomato shoots. Hydrogen peroxide content as an index of oxidative stress was also measured. Inhibitory effects on ascorbate peroxidase, dehydroascorbate reductase and ascorbate, and stimulatory effects on glutathione reductase, monodehydroascorbate reductase and reduced glutathione were observed when tomato plants were simultaneously treated with BEA and T-2. The trends of these biochemical parameters highlight the presence of a range of defence mechanisms activated by plants in response to mycotoxins. The interaction between BEA and T-2 resulting in synergistic and/or antagonistic effects on the studied defence systems is also discussed. It is concluded that the effects of these mycotoxins alone are not predictive of their combined effects
Miscele eutettiche come solventi biocompatibili a basso impatto ambientale per l’estrazione e la determinazione di metaboliti secondari fungini in matrici alimentari
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Global risk maps for mycotoxins in wheat and maize
No full textAbstract
This chapter maps the worldwide risk for mycotoxin contamination with focus on deoxynivalenol in wheat and on fuminisin and aflatoxins in maize. A modelling approach was taken with meteorological data as input. FAO databases were used both to define crop distribution and as a meteorological data source. Simple existing models developed to predict mycotoxin contamination at harvest were adapted and used for the global forecasting. Risk maps were drawn by overlapping the layer of countries with significant wheat/maize growing areas, a North and South latitude filter (60° and 55° respectively for wheat and maize), and risk as assessed by predictive criteria.
The idea of mapping mycotoxin risk in wheat and maize worldwide is ambitious because of the large amount of data required. Predictive maps are drawn as mean maps and do not consider annual and local variations, but instead stress main problems in particular areas. Annual local surveys, in specific years, may suggests a different picture of the mycotoxin risk. These discrepancies are expected because of the simple modelling approach adopted and because only meteorological data have been taken into account. Nevertheless, this simple model could provide the basis for global comparisons. The long term goal is to study the occurrence of mycotoxins and related fungi, to monitor crop phenology and cropping system, and to store meteorological data in a broadly accessible manner
Antagonistic effect of beauvericin and T-2 toxin co-occurence on antioxidant defence systems in tomato plants
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Molecular characterization of Pleurotus eryngii varieties occurring in Italy
No full textThe Pleurotus eryngii species complex is an economically important group which includes several closely related varieties, whose genetic discrimination is still not clear. One hundred and ten Italian strains of Pleurotus eryngii belonging to the varieties elaeoselini, eryngii, ferulae and thapsiae and P. nebrodensis were analysed by sequencing two housekeeping genes (ef1-a and rpb2), in order to find molecular markers for the identification of different varieties. Sequence analysis of partial ef1-a and rpb2 genes, allowed identification of some conserved nucleotide positions within each variety but variable among var. elaeoselini, var. eryngii, var. ferulae var. thapsiae and P. nebrodensis, allowing their discrimination. Phylogenetic analysis from the data of the two genes data set showed that var. elaeoselini, var. thapsiae, var. ferulae and var. eryngii are closely related to each other, and confirm P. nebrodensis as a separate clade
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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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