TaqMan probe assays on different biological samples for the identification of three ambrosia beetle species, Xylosandrus compactus (Eichoff), X. crassiusculus (Motschulsky) and X. germanus (Blandford) (Coleoptera Curculionidae Scolytinae)

Molecular assays based on qPCR TaqMan Probes were developed to identify three species of the genus Xylosandrus, X. compactus, X. crassiusculus and X. germanus (Coleoptera Curculionidae Scolytinae). These ambrosia beetles are xylophagous species alien to Europe, causing damages to many ornamental and fruiting trees as well as shrubs. DNA extraction was carried out from adults, larvae and biological samples derived from insect damages on infested plants. For X. compactus, segments of galleries in thin infested twigs were cut and processed; in the case of X. crassiusculus, raw frass extruded from exit holes was used, while DNA of X. germanus was extracted from small wood chips removed around insect exit holes. The assays were inclusive for the target species and exclusive for all the non-target species tested. The LoD was 3.2 pg/μL for the frass of X. crassiusculus and 0.016 ng/μL for the woody matrices of the other two species. Both repeatability and reproducibility were estimated on adults and woody samples, showing very low values ranging between 0.00 and 4.11. Thus, the proposed diagnostic assays resulted to be very efficient also on the woody matrices used for DNA extraction, demonstrating the applicability of the protocol in the absence of dead specimens or living stages

L’ARTICOLAZIONE ARGOMENTATIVA DI PLAT. SOPH. 237B7-239A11 E LA NATURA DEL MEDAMOS ON

In Soph. 237b7-239a11 Plato lays out a sequence of arguments that are generally considered homogenous. An analysis of each argument can shed light on the need to differentiate their respective nature. Firstly, it will be shown that the arguments do not work only at the linguistic level, contrary to the way these passages are interpreted by most of commentators. The meta-linguistic nature of the third argument will be particularly emphasised. Secondly, it will be argued that the three arguments follow each other according to a crescendo. The implications of this argumentative structure will be specifically appreciated. Both these results of the analysis induce to attribute a crucial importance to the notion of medamos on: the arguments do not aim to definitively exclude the possibility of a Parmenidean non-being; they play a positive role within the inquiry of the Stranger of Elea, inasmuch the thematisation of Parmenidean non-being is seriously taken into account and embraced at this stage of the dialogue. In fact it is only through this dialectical step that the Stranger gains the chance to proceed in the direction of a relational ontology and a new concept of non-being. The positive role played by the medamos on presupposes that this expression and the equivalent ones are not mere absurdities and can find place in the Platonic use of language; this implies that the notion of medamos on must have a justification in the framework of Platonic relational ontology and conception of language. The consideration of this aspect eventually gives the opportunity to return to the three arguments and present an explanation of their positioning in that stage of the dialogue