1,720,981 research outputs found
Phenotypic and genotypic characterization of Italian <em>Phytophthora infestans</em> isolates
Full text linkPhytophthora infestans (Mont.) de Bary causes late blight of potato. After the 1970s, several changes have occurred in the European P. infestans population, frequently associated with an increased virulence. While the genotypic and phenotypic diversity of P. infestans has been studied in-depth in northern and central Europe, only a few reports are available regarding Italian isolates, mainly based on phenotypic traits. We report data of phenotypic and genotypic characteristics of isolates collected from infected potato and tomato plants in different Italian regions in 2006‒2008. A prevalence of the A1 mating type and a majority of metalaxyl-resistant isolates were found. Tomato-derived isolates showed fungicide sensitivity, confirming previous reports. One of the isolates showed the rare IIb mitochondrial DNA haplotype. Genetic analyses of the single-sequence repeats (SSRs) and of the internal transcribed spacers gave similar results, although SSRs gave the best discrimination of genotypes
Evaluating the survival and environmental fate of the biocontrol agent Trichoderma atroviride SC1 in vineyards in northern Italy
No full textTo study the survival in the soil and the dispersion in the environment of Trichoderma atroviride SC1 after soil applications in a vineyard. METHODS AND RESULTS: Trichoderma atroviride SC1 was introduced into soil in two consecutive years. The levels of T. atroviride populations at different spatial and temporal points following inoculation were assessed by counting the colony-forming units and by a specific quantitative real-time PCR. A high concentration of T. atroviride SC1 was still observed at the 18th week after inoculation. The vertical migration of the fungus to a soil depth of 0.4 m was already noticeable during the first week after inoculation. The fungus spread up to 4 m (horizontally) from the point of inoculation and its concentration decreased with the increasing distance (horizontal and vertical). It was able to colonize the rhizosphere and was also found on grapevine leaves. One year after soil inoculation, T. atroviride SC1 could still be recovered in the treated areas. CONCLUSIONS: Trichoderma atroviride SC1 survived and dispersed becoming an integrant part of the local microbial community under the tested conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: The persistence and rapid spread of T. atroviride SC1 represent good qualities for its future use as biocontrol agent against soilborne pathogens
DNA analysis in wines: development of methods for anhanced extraction and real-time polymerase chain reaction quantification
No full textReliable methods for DNA traceability in grapevines and wines is in great demand for protecting areas of declared origin and detecting potential transgenic events. Currently, real-time polymerase chain reaction (PCR) is one of the most promising tools for conducting plant and microorganism DNA assays and detecting genetically modified material. However, in grape, quantitative analysis based on PCR is lagging behind. Moreover, in musts and wines, efficient DNA extraction and amplification need to be developed. In the present research, we compared several DNA extraction procedures on various grape tissues, musts and wines of the Trentino-Südtirol Region. We chose the Vitis vinifera nine-cis-epoxycarotenoid dioxygenase2 (VvNCED2) gene as the referee standard in grape and tested for validation. Using real-time PCR, with VvNCED2 as standard referee, we successfully quantified grape DNA from grape tissues and the residual grape DNA in musts and wines. In addition, we also quantified the S. cerevisae residual DNA in wines. Extracted grape DNA quality and specificity were also verified by co-dominant simple sequence repeat (SSR) markers. SSRs proved that, even 1 year after wine fermentation, we could detect and identify grape DNA that was still suitable for analysis. Our research is the first successful report of efficient DNA extraction, amplification and real-time PCR quantification for aged wines. As a result, we could count on a suitable assay for tracing and monitoring endogenous and exogenous DNA in grape and grape products. © 2005 Elsevier B.V. All rights reserved
Impact of the biocontrol agent Trichoderma atroviride Sc1 on soil microbial communities of a vineyard in Northern Italy
No full textThe fungus Trichoderma atroviride SC1 is an experimental biocontrol agent (BCA) that is active against the fungus Armillaria mellea. Following the application of Trichoderma to the surface soil of a vineyard, we used a highly specific real-time PCR, previously validated for the analysis of soil microcosms, to monitor the populations of this fungus at different soil depths over several months. The quantification obtained using this molecular method was highly correlated with laboratory assays of colony-forming units. The native communities of bacteria and fungi in the soil were analyzed using automated ribosomal intergenic spacer analysis (ARISA), and transient changes were observed following the application of T. atroviride SC1 conidia. A principal component of variance analysis demonstrated that the introduction of T. atroviride SC1 had an effect on the soil microflora during the first two weeks following inoculation. However, at later dates, environmental conditions had a higher influence on the surveyed communities than the BCA application, as confirmed through the use of the Shannon index of biodiversity. Soil depth had a strong influence on the composition and biodiversity of fungal communities. © 2009 Elsevier Ltd. All rights reserved
Real-time PCR for detection and quantification of the biocontrol agent Trichoderma atroviride strain SC1 in soil
No full textTrichoderma (Hypocreales, Ascomycota) is a widespread genus in nature and several Trichoderma species are used in industrial processes and as biocontrol agents against crop diseases. It is very important that the persistence and spread of microorganisms released on purpose into the environment are accurately monitored. Real-time PCR methods for genus/species/strain identification of microorganisms are currently being developed to overcome the difficulties of classical microbiological and enzymatic methods for monitoring these populations. The aim of the present study was to develop and validate a specific real-time PCR-based method for detecting Trichoderma atroviride SC1 in soil. We developed a primer and TaqMan probe set constructed on base mutations in an endochitinase gene. This tool is highly specific for the detection and quantification of the SC1 strain. The limits of detection and quantification calculated from the relative standard deviation were 6000 and 20,000 haploid genome copies per gram of soil. Together with the low throughput time associated with this procedure, which allows the evaluation of many soil samples within a short time period, these results suggest that this method could be successfully used to trace the fate of T. atroviride SC1 applied as an open-field biocontrol agent. © 2008 Elsevier B.V. All rights reserved
Apple allergens genomics and biotechnology: unravelling the determinants of apple allergenicity
No full textAbstract
In the last decades allergies are increasing in the western countries and different protein families were identified as determinants of allergenicity. In apple fruit, one of the most important fruit crop in the world, four allergen families (Mal d 1 to 4) have been identified so far, including pathogenesis-related proteins 10, thaumatin-like proteins, lipid-transfer proteins and profilins. Moreover, it has been demonstrated that patient’s sensitivity differs in relation to apple variety, fruit tissue, cultivation and conservation conditions, increasing the difficulties to associate genetic, molecular and biochemical data with the results of clinical tests. Mapping studies and the availability of the complete apple genome sequence confirmed that allergens are organized in large families with many different isoforms, which contribution to allergenicity is still largely unknown. The unravelling of allergy determinants is crucial for different reasons: i) to better understand environmental influences on allergenicity; ii) to produce genetically modified plants with a reduced allergen content through a targeted-gene silencing approach and iii) to drive future breeding programs toward hypoallergenic apple through the exploitation of natural variability. Finally, the above-mentioned knowledge will be essential to allow the consumption of this fruit by individuals who are allergic to apple
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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