1,721,179 research outputs found
Identification and detection of Rosellinia necatrix by conventional and real-time Scorpion PCR
No full textSeveral polymerase chain reaction (PCR) primers were designed from the internal transcribed spacer (ITS) regions of the rDNA genes of Rosellinia necatrix to develop a PCR-based identification method. Screening the primers against two isolates of R. necatrix and six other Rosellinia species resulted in the amplification of a single specific product from R. necatrix for most of the primer pairs. Two primer pairs (R2-R8 and R10-R7) confirmed their specificity when tested against 72 isolates of R. necatrix and 93 other fungi from different hosts and geographic areas. The R10 primer was modified to obtain a Scorpion primer for detecting a specific 112 bp amplicon by fluorescence emitted from a fluorophore in a self-probing PCR assay. This assay specifically recognised the target sequence of R. necatrix over a large number of other fungal species. In conventional PCR, with primer pairs R2-R8 and R10-R7, 10-fold dilutions of R. necatrix DNA indicated a detection limit of 10 pg muul(-1) using a single set of primers and 10 fg mul(-1) in nested-PCR. For Scorpion-PCR, the detection limit was 1 pg mul(-1) and 1 fg mul(-1) in nested Scorpion-PCR, i.e. 10 times more sensitive than conventional PCR. A simple and rapid procedure for DNA extraction directly from soil was modified and developed to yield DNA of purity and quality suitable for PCR assays. Combining this protocol with the nested Scorpion-PCR procedure it has been possible to specifically detect R. necatrix from artificially inoculated soils in approximately 6 h
Presentazione [L'italiano lingua utilitaria]
No full textPresentazione del libro: L'italiano lingua utilitari
Rapid and sensitive detection of Rosellinia necatrix in roots and soils by real time Scorpion-PCR
No full textResoconto di un 'divertissement' grammaticale sul congiuntivo in italiano e nel dialetto di Bormio
No full textLa scoperta della cronogenesi mostra l'affidabilità del metodo di Gustave Guillaume, fondato sul tempo operativo. In maniera semplice e complessa al tempo stesso, la sua «linguistique de position» spiega i modi secondo intercettazioni del processo di formazione dell’immagine-tempo da parte del soggetto locutore che intende situare un’azione nel tempo. Nella comparazione dei dati italiano standard/varietà bormina è stato stabilito un rapporto tra le cosiddette sollecitazioni mentali «silenziose» delle forme modali del congiuntivo e la loro espressione, mettendo in relazione critica l'approccio semasiologico tradizionale e quello onomasiologico del metodo psicomeccanico
Induction of resistance in sweet cherry fruits treated with salts and Aureobasidium pullulans
No full textEnseigner et apprendre le jeu modal: question de méthode
No full textLe subjonctif a reçu maintes définitions selon les différents signifiés des phrases où il apparaît. Toutefois, malgré l’extrême hétérogénéité du discours, le système présente une syntaxe cohérente. Cet aspect est généralement admis, mais les approches pédagogiques ne proposent pas un modèle unitaire d’interprétation du mode subjonctif. Elles mettent l’accent sur les formes et sur les moyens de les assimiler dans le bon contexte, mais n’enquêtent pas sur les raisons de leur emploi. L’idée de présenter la psychomécanique du langage à des étudiants universitaires est motivée par le fait que cette théorie condense de multiples effets à travers les régularités des interceptions du temps opératif. Grâce à cet appareil théorique, les apprenants comprennent les deux volets du langage : la complexité de l’effectif et la simplicité du potentiel. La charpente du mode est décrite de façon à ce que les apprenants trouvent un lien entre leur activité psychique et leur production langagière. Le fait de dévoiler l’ « ordre secret » du discours, confirmant ainsi que la langue est systématique, les encourage à rechercher les éléments communs sous-jacents. Pour les aider à travailler de manière inductive, on trace d’abord les lignes de force générales de l’emploi du subjonctif. La méthode pédagogique s’avère ainsi un va-et-vient de la théorie à l’analyse des faits langagiers tirés de la presse, mais aussi d’ouvrages littéraires, la diversité des genres écrits étant importante pour comprendre la simplification actuelle du système « à quatre temps » du subjonctif. La théorie guillaumienne contribue à renforcer l’intuition des apprenants quand elle est pédagogisée pour développer non seulement un savoir grammatical, mais aussi une conscience linguistique, quand elle est inscrite dans la méthode de « linguistique-didactique » pour transmettre des compétences et affiner une certaine sensibilité à l’égard du binôme langue-culture
Real time detection and quantification of soilborne fungal pathogens: the case of Rosellinia necatrix, Phytophthora nicotianae, P. citrophhtora and Verticillium dahliae
Full text linkConventional and Scorpion primers were designed from the ITS regions to identify Rosellinia necatrix,
Phytophthora nicotianae, and P. citrophthora and from the IGS regions to identify Verticillium dahliae and V. alboatrum.
Specificity of primers and probes was assessed using genomic DNA from a large number of fungi from several
hosts and by means of BLAST analyses, to exclude the presence of similar sequences in other micro-organisms
among available DNA databases (GenBank). Simple and rapid procedures for DNA extraction from naturally infected
matrices (soils, roots, bark, and/or woody tissues) were utilised to yield DNA of a purity and quality suitable for
PCR assays. Combining these protocols with a double amplification (nested Scorpion-PCR), the real-time detection of
these pathogens was possible from naturally infested soils and from infected citrus roots (P. nicotianae and P.
citrophthora), from the roots and bark of stone fruits and olive (R. necatrix) and from olive branches (V. dahliae). For
target pathogens, the limit of detection was 1 pg µl-1 in Scorpion-PCR and 1 fg µl-1 in nested Scorpion-PCR. High and
significant correlations between pathogen propagule concentrations and real-time PCR cycle thresholds (Ct) were
obtained. Moreover, specific tests with R. necatrix seem to indicate that its DNA is quite rapidly degraded in the soil,
excluding the risk of false positives due to the presence of dead cells
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